Category: CBSE Class 9

Forest Society and Colonialism Class 9 Extra Questions History Chapter 4

Question 1.
How much-cultivated area rose during 1880-1920?
Answer:
The cultivated area rose by 9.7 million hectares between 1880 and 1920.

Question 2.
Why was railways essential to the colonial rulers?
Answer:

• For colonial trade,
• movement of troops.

Question 3.
Which places did the Indus Valley Railway touch when introduced?
Answer:
Multan on the one hand and Sukkur on the other hand, a distance of nearly 300 miles.

Question 4.
Which places were joined together by the Northern State Railway?
Answer:
Lahore on the one hand and Multan on the other.

Question 5.
Who was Dietrich Brandis and who appointed him?
Answer:
Dietrich Brandis was a German forest expert. The British Government appointed him as Inspector General of Forests in India.

Question 6.
When was the Indian Forest Act passed?
Answer:
The Indian Forest Act was passed in 1865.

Question 7.
Which Act divided the forest into reserved, protected and village forests?
Answer:
The Act of 1878.

Question 8.
Could the villagers according to the Act of 1878, make use of the reserved forests?
Answer:
The villagers could not take anything from the reserved forests, even for their own use.

Question 9.
What is scientific forestry?
Answer:
Scientific forestry is a system of cutting trees Controlled by the forest department in which old trees are cut and new ones planted.

Question 10.
What is lading?
Answer:
Lading is local name for shifting cultivation of Southeast Asia. In Central America, it is called milpa, while in Sri Lanka, it is called Chena.

Question 11.
Why did the colonial government decide to ban shifting cultivation? Give one reason.
Answer:
It was difficult for the government to calculate, taxes on shifting cultivation.

Question 12.
Name some of the nomadic and pastoral communities of Madras Presidency.
Answer:
Korava, Karacba, and Yerukula.

Question 13.
Name the leaders of the movements of Santhal Pargana, Chhotanagpur, Andhra Pradesh who resisted the British colonialists.
Answer:

• Santhal Pargana: Siddhu & Kanu
• Chhotanagpur: Birsa Munda
• Andhra Pradesh: Alluri Sitarama Raju.

Question 14.
Who were the Kalangs?
Answer:
The Kalangs were a community- of Java (Indonesia) who were skilled forest cutters and shifting cultivators.

Question 15.
“The forest area is. fast disappearing”. Substantiate.
Answer:
The forest area indeed is fast disappearing. Between 1700 and 1995, which may be characterized as the period of industrialization, 13.-9 million sq km of forests or 9.3% of the world’s total areas had been cleared for

• industrial use,
• cultivation,
• pasture’s, and fuelwood.

Question 16.
What were the banana republics?
Answer:
The power of an American owned United Fruit Company to grow bananas on the large industrial scale, in Central America is said to be banana republics.

Question 17.
Should the land unused be improved or remain with the Aboriginals,? Give your arguments.
Answer:
The land unused remains unproductive. It may be in regions like the Central America or Australia. It is important that the land be used or improved upon so to be productive. It is the land that helps us grow crops, and take from it numerous natural resources. The land wasted is the land lost. It is important that the people make use of it, and make it productive.

Question 18.
As the oak forests were disappearing, how did England manage to have timber for its shipbuilding requirement?
Answer:
By the early nineteenth century, oak forest in England were disappearing. This created a problem of timber supply for the Royal Navy. By 1920s, search parties were sent to explore the forest resources of India. Within a decade, trees were being felled on a massive scale and vast quantities of timber were being exported from India.

Question 19.
Write a brief note on scientific forestry. ‘
Answer:
The Imperial Forest Research Institute, set up at Dehradun in 1906, taught what is called scientific forestry. In scientific forestry, natural forests which had lots of different types of trees were cut down. In their place, one type of tree was planted in straight rows.

This is called a plantation. Forest officials surveyed the forests, estimated the area under different types of trees, and made working plans for forest management. The colonial rulers planned how much of the plantation area was to be cut every year. The area cut was then to be replanted so that it was ready to be cut again in some future years.

Question 20.
What were the forest Acts and what characteristics they had?
Answer:
After the Forest Act was enacted in 1865, it was amended twice, once in 1878 and then in 1927. The 1878 Act divided forests into there categories; reserved, protected and village forests. The best forests were called ‘reserved forests’. Villagers could not fake anything from these forests. For house building or fuel, they could take the wood.

Question 21.
Give the status of the Bastar region.
Answer:
In 1947 Bastar kingdom was merged with Ranker kingdom and became Bastar district in Madhya Pradesh. In 1998 it was divided again into three districts, Ranker, Bastar and Dantewada. In 2001, these became part of Chhattisgarh. Tire 1910 rebellion first started in the Kanger forest area and soon spread to other parts of the state.

Question 22.
Mention the location of the Bastar region. ?
Answer:
Bastar is located in the southernmost part of Chhattisgarh and borders Andhra Pradesh/Orissa and Maharashtra. The central part of Bastar is on a plateau. To the north of this plateau is the Chhattisgarh plain and to its South is the Godavari plain. The river Indrawati winds across Bastar east to west.

Question 23.
What is deforestation? How has cultivation been responsible for clearing of forests.
Answer:
The disappearance of forests is deforestation. The process of deforestation has become more systematic and extensive during the colonial rule. In 1600 about one-sixth of India’s landmass was under cultivation. Now the figure has gone up to about half. As population grew, so grew the demand for food, and so began the process of cultivation.

In the colonial period, cultivation expanded rapidly. Two major reasons were: first, the British directly encouraged the production of commercial crops like jute, sugar, wheat and cotton. The demand, for these crops, increased in nineteenth century. Secondly, in early 19th century, the colonial state thought that the forests Were unproductive and that land cultivation would not only yield agricultural products/but also revenue for the state. That is why we find that between 1880 and 1920, cultivation area rose by 9.7 million hectares.

Question 24.
Why did the British make use of timber for railway in India? Explain.
Answer:
The spread of railways, ever since 1850, created a new demand. Railways were essential for colonial trade and for the movement of troops. To run locomotives, wood was needed as fuel, and to lay railway lines, sleepers were essential to hold the tracks together. From the 1860s, the railway network expanded rapidly. By 1890′, about 25,500 km of track had been laid. In 1946, the length of the tracks had increased to over 765,000 km.

As the railway tracks spread through India, a larger and larger number of trees were felled. As early as the 1,850s, in the Madras. Presidency alone, 35,000, trees were being cut annually for sleepers. The government gave out contracts to individuals to supply the required quantities. These contractors began cutting trees indiscriminately. Forests around the railway tracks fast started disappearing.

Question 25.
How did the forest laws bring days of hardships for the villagers? Explain.
Answer:
The villagers had the face the days of hardships because of the stricter forest laws. After these Acts, all their everyday practices-cutting wood for houses, grazing their cattle, collecting fruits and roots, hunting and fishing became illegal.

People were now forced to steal wood from the forests, and if they were caught, they were at the mercy of the forest guards who would take bribes from them. Women who collected fuelwood were especially worried. It was also common for police constables and forest guards to harass people for demanding free food from them.

The villagers had to abandon the shifting cultivation, for the government restricted this type of farming due to heavy losses of timber burnt during the process. It felt that land which was used for cultivation every few years could not grow trees for railways timber. When a forest was burnt, there was the added danger of the flames spreading and burning valuable timber.

Shifting cultivation also made it harder for the government to calculate taxes. Therefore, the government decided to ban shifting cultivation. As a result, many communities were forcibly displaced from their homes in the forests. Some had to change occupations, while some resisted through large and small rebellions.

Question 26.
Write short notes on the following:
(i) Dutch Scientific Forestry.
(ii) Sarnin’s challenge.
Answer:
(i) Dutch Scientific Forestry In the nineteenth century, when it became important to control territory and not just people, the Dutch enacted forest laws in Java, restricting villagers access to forests. Now wood could only be cut for specified purposes like making riverboats or constructing houses, and only from specific forests under close supervision. Villagers were punished for grazing cattle in young stands, transporting wood without a permit, or travelling on forest roads with horse carts or cattle.

(ii) Samin’s challenge-Around 1890, Surontiko, Samin of Randbulafung village, a teak forest village, began questioning state ownership of tine forest. He argued that the state had not created the wind, water, early and wood, so it could not own it. Soon a widespread movement developed. Amongst those who helped organise it were Samin’s sons-in-law. By 1907, 3,000 families were following his ideas. Some of the Saminists protested by lying down on their land when the Dutch came to survey it, while others refused to pay taxes or fines or perform labour.

Objective Type Questions

1. Select correct (✓) or wrong (✗) from the following:

Question 1.
Banana Republics belong to regions such as the Central America.
Answer:
(✓)

Question 2.
Railway tracks required, at one point of time, wooden sleepers.
Answer:
(✓)

Question 3.
Brandis was an English forest expert.
Answer:
(✗)

Question 4.
Indian Forest Service was set up in 1865.
Answer:
(✗)

Question 5.
George Yule killed 400 tigers.
Answer:
(✓)

2. Select the correct word from the four alternatives given herein:

Question 1.
Bastar is bordered by the following :
(a) Orissa
(b) Tamil Nadu
(c) Karnataka
(d) Rajasthan
Answer:
(a) Orissa

Question 2.
Gunda Dhur belonged to the following village:
(a) Bastar
(b) Jagdalpur
(c) Nathan
(d) Palam
Answer:
(c) Nathan

Question 3.
Java is a place in:
(a) Thailand
(b) Singapore
(c) Indonesia
(d) Myanmar.
Answer:
(c) Indonesia

Question 4.
The Imperial Forest Research Institute was set up at :
(a) Hard war
(b) Dehradun
(c) Kashipur
(d) Badali
Answer:
(b) Dehradun

Question 5.
The forest act, first, was passed in :
(a)1864
(b) 1S66
(c) 1865
(d) 1867.
Answer:
(c) 1865

3. Fill in the blanks with the words given in the brackets:

Question 1.
In the Madras Presidency, as early as 1850s, about 35000 trees were cut ……………………… (annually, six-monthly)
Answer:
annually

Question 2.
Brandis was a forest expert ……………………… . (German, Brazilian)
Answer:
German

Question 3.
The Imperial Forest Research Institute was set up at Dehradun in ……………………… (1905,1906)
Answer:
1906

Question 4.
George Yule was a …………………….. administrator. (German, Dutch)
Answer:
British.

Extra Questions for Class 9 Social Science

In this page, we are providing Natural Resources Class 9 Extra Questions and Answers Science Chapter 14 pdf download. NCERT Extra Questions for Class 9 Science Chapter 14 Natural Resources with Answers will help to score more marks in your CBSE Board Exams. https://ncertmcq.com/extra-questions-for-class-9-science/

Class 9 Science Chapter 14 Extra Questions and Answers Natural Resources

Extra Questions for Class 9 Science Chapter 14 Natural Resources with Answers Solutions

Natural Resources Class 9 Extra Questions Very Short Answer Type

Natural Resources Class 9 Extra Questions Question 1.
What are the resources available on Earth for life to exist?
Answer:
Air, water and land are the resources available on the Earth which help life to exist.

Natural Resources Class 9 Important Questions Question 2.
Name the compound of carbon responsible for the ozone hole in the atmosphere.
Answer:
Chlorofluorocarbons (CFC’s) are responsible for the ozone hole in the atmosphere.

Class 9 Science Chapter 14 Extra Questions And Answers Question 3.
State the temperature range on the surface of the moon.
Answer:
The temperature ranges from -190°C to 110°C on the moon

Natural Resources Class 9 Extra Questions And Answers Question 4.
State any one difference between oxygen and ozone.
Answer:
Oxygen is a diatomic molecule with formula 02 whereas ozone is a triatomic molecule-with formula 0₃.

Extra Questions For Class 9 Science Chapter 14 Natural Resources Question 5.
Name the stage in the life cycle of aquatic animals which is affected by a change in temperature.
Answer:
The stage of animals which is affected by the change in the temperature is – the eggs at the hatching stage, the larvae and the young ones of the animals.

Extra Questions Of Natural Resources Class 9 Question 6.
Along with the natural resources available on the Earth, what else is required to meet the basic requirements of all life forms on the Earth?
Answer:
Solar energy is required to meet the basic requirements of all life forms on Earth.

Natural Resources Class 9 Questions And Answers Question 7.
How is biosphere a dynamic and stable system?
Answer:
There is a constant interaction between the biotic and the abiotic components of the global ecosystem (biosphere) which makes it a stable system. The basic composition and the structure of the system do not change while carrying out the various processes. So, it is a stable system.

Natural Resources Extra Questions Question 8.
How do forests play a major role in maintaining the water cycle?
Answer:
The amount of water vapour in the atmosphere is dependent on the transpiration of water from the leaves of the plants present in a forest. Also, the storage of water in watershed is influenced by the forests. So, forests play a major role in maintaining the water cycle.

Ch 14 Science Class 9 Extra Questions Question 9.
Why is step farming done in hills?
Answer:
Step farming is done in hills to prevent soil erosion by slowing down the speed of the water running down the slopes.

Class 9 Natural Resources Extra Questions Question 10.
Why are root nodules useful for plants?
Answer:
The root nodules of leguminous plants contain nitrogen-fixing bacteria like the Rhizobium which help to increase the fertility of the soil by fixing atmospheric nitrogen.

Class 9 Science Ch 14 Extra Questions Question 11.
What are the biotic and the abiotic components of the biosphere?
Answer:

• Biotic component: comprises of living things.
• Abiotic component: comprises of non-living things like temperature, rainfall, air, water and soil.

Questions On Natural Resources Class 9 Question 12.
What percentage of oxygen and nitrogen are present in the atmosphere?
Answer:
The approximate percentage of oxygen and nitrogen in the atmosphere are:
Oxygen: 21%, Nitrogen: 78%

Extra Questions On Natural Resources Class 9 Question 13.
Give the major source of minerals in the soil.
Answer:
The minerals in the soil depend upon the rocks from which the soil is formed. So, the rocks are the major source of minerals in the soil.

Natural Resources Class 9 Important Questions With Answers Question 14.
Name the two gases given out during the burning of fossil fuels which dissolve in rain to form acid rain.
Answer:
Sulphur dioxide and oxides of nitrogen.

Extra Questions Of Chapter Natural Resources Class 9 Question 15.
Name the group of compounds responsible for ozone layer depletion.
Answer:
Chlorofluorocarbons (CFCs) are responsible for ozone layer depletion.

Natural Resources Class 9 Extra Questions Short Answer Type 1

Question 1.
What are the sources of oxygen in the atmosphere?
Answer:
The sources of oxygen in the atmosphere are:

• Oxygen released during photosynthesis by plants
• The dissociation of oxides from their compounds
• The disintegration of ozone in presence of UV rays
• As the water in combined form

Question 2.

1. What causes winds?
2. List any two methods of preventing soil erosion.

Answer:

1. Due to the unequal heating of land and water, the land get heated up faster during the day, the air on land rises up and creates a region of low pressure. As a result, the air over the sea moves towards the region of low pressure formed on the land. This causes winds to flow.

2. (a) Overgrazing by cattle should be avoided.
(b) Large scale afforestation should be done as roots of plants prevent the soil from getting carried away.
(c) Increasing the vegetation cover on the ground reduces the impact of flowing water on soil and prevents it from getting washed away.
(d) Contour farming can be done by ploughing the land in furrows across the natural slope of the land to trap water flowing down.
(e) Step farming is practised in hilly regions which reduce the flow of water and give it more time to percolate into the soil.

Question 3.
List the importance of oxygen gas and ozone gas in the atmosphere.
Answer:
Role of Oxygen gas: It helps in the process of combustion, respiration and formation of many organic compounds.
Role of Ozone: It absorbs the harmful UV rays of the Sun which can cause skin diseases and cancer on reaching the Earth’s surface.

Question 4.
Mention one method by which living organisms influence the formation of soil.
Answer:
The living organisms like lichens and mosses are the initial colonisers of rocks which secrete certain chemical substances that dissolve the minerals of rock and cause the gradual weathering of rocks. The rocks get broken down into small, fine particles of soil. So, living organisms play an important role in the formation of soil.

Question 5.
Explain the occurrence of land breeze in coastal areas.
Answer:
During the day, in coastal regions, the air above land gets heated faster and warm air being lighter rises up thereby creating a region of low pressure. The air over the sea then moves towards the area of low pressure. The movement of air from one region to the other creates winds. At night, water cools down slower than the land, so the air above water would be warmer than the air above land. This causes air over the land to move towards the region of low pressure over water.

Question 6.
What are the two ways in which carbon dioxide is fixed in the environment?
Answer:
Carbon dioxide is fixed in the atmosphere when:

1. Green plants utilise the carbon dioxide and convert it into glucose during photosynthesis.
2. Carbon dioxide dissolved in seawater in the form of carbonates gets used up by the marine animals for the formation of their shells.

Question 7.

1. Why do terrestrial forms require freshwater?
2. Give two examples where freshwater can be found in the frozen form on the Earth.

Answer:

1. The terrestrial organisms require freshwater as they face osmotic problems if kept in marine water because they have low osmotic concentration. In order to maintain the balance of the salts present in their body, freshwater organisms require a medium having less salt concentration i.e., freshwater.
2. Freshwater can be found in a frozen form at polar ice-caps and the glaciers.

Question 8.
What is the role of the atmosphere in climate control?
Answer:
The atmosphere acts as a buffer which checks excessive rise in temperature during the day and prevents excessive cooling of the Earth during the night. The atmosphere helps to keep the average temperature of the Earth steady.

Question 9.
State any two harmful effects of air pollution.
Answer:
The two harmful effects of air pollution are:

1. Respiratory problems and difficulty in breathing
2. Acid rains

Question 10.
1. Define the term ‘smog’.
2. Name any two types of disease caused by regularly breathing polluted air.
Answer:
1. Smog is a kind of air pollution, named for the mixture of smoke and fog in the air. The thick cloud of water droplets having smoke particles suspended in the atmosphere which restricts visibility is called smog.
2. Diseases caused by breathing polluted air are:
(a) Allergy
(b) Respiratory disorders
(c) Heart-related problems

Question 11.
Mention a cause and a consequence of acid rain.
Answer:
Cause of acid rain: The oxides of nitrogen and sulphur like nitrogen dioxide and sulphur dioxide released from the burning of fossil fuels gets mixed with water vapour present in the atmosphere to form acids. These acids dissolve in the rainwater and fall as acid rain on the Earth.

A consequence of acid rain:

1. The fertility of soil gets reduced due to the acidity created in the soil by the acid rains.
2. Acid rain corrodes the historic monuments and structures made of marble, metals, painted surfaces, etc.
3. The aquatic life is also harmed due to excess amount of acids which gets dissolved in water by acid rains.

Question 12.
What is meant by biogeochemical cycle? Name the two essentials which are transferred between different components of the biosphere.
Answer:
The movement of nutrient elements through the various components of an ecosystem i.e., biotic and the abiotic components, is called a biogeochemical cycle.
The two essentials which are transferred between different components of the biosphere are: Matter and energy,

Question 13.
What is the difference between nitrification and denitrification?
Answer:
Nitrification:
The process by which ammonia or ammonium compounds is converted into nitrites by Nitrosomonas and nitrites into nitrates by the Nitrobacter is called nitrification.

Denitrification:
The process by which the nitrites or nitrates are broken down into elemental nitrogen (N₂) by Pseudomonas or Thiobacillus is called denitrification.

Question 14.
Draw a well-labelled diagram to show the carbon cycle in nature.
Answer:

Question 15.
State the role of photosynthesis and respiration in the carbon cycle.
Answer:
Photosynthesis: Carbon dioxide in the atmosphere is fixed by green plants during the process of photosynthesis and converted into glucose.

Respiration: Glucose is oxidised during respiration to obtain energy. Carbon dioxide gets released during the process and is returned to the atmosphere. In this way photosynthesis and respiration help in maintaining the carbon cycle in nature.

Question 16.
Draw a neat labelled diagram to show the nitrogen cycle.

Question 17.
Name any four carbon-containing molecules which are essential for human beings.
Answer:
The carbon-containing molecules essential for human beings are:

1. Deoxyribonucleic acid-DNA
2. Proteins
3. Carbohydrates
4.  Fats

Question 18.
Draw a well-labelled diagram to show the oxygen cycle in nature.
Answer:

Question 19.
(a) Why do terrestrial forms require freshwater?
(b) Mention any two processes involved in the water cycle.
Answer:
(a) Terrestrial forms require water for carrying out the various cellular and metabolic process which occur in their body.
(b) Two processes involved in the water cycle are: Evaporation of water from water bodies and precipitation of water in the form of rain, hail or snow.

Question 20.
What is the importance of greenhouse gases present in the atmosphere?
Answer:
The greenhouse gases like carbon dioxide and methane prevent the escape of heat from the Earth. Thus, these gases play an important role of keeping the average temperature of the Earth constant.

Question 21.
What is the greenhouse effect? What will happen if the concentration of greenhouse gases increase in the air?
Answer:
The phenomenon in which the incoming sunlight is allowed to pass through the atmosphere but heat radiated back from the planet’s surface is trapped by the gases like carbon dioxide, water vapour and methane present in the atmosphere is called the greenhouse effect.

Increase in concentration of greenhouse gases would prevent the escape of heat from the Earth, increase the average temperature worldwide and result in global warming. Global warming will cause a rise in sea and odd climatic changes due to faster melting of glaciers and polar ice caps.

Natural Resources Class 9 Extra Questions Short Answer Type 2

Question 1.
1. The circulation of carbon is important in nature. Give reasons for your answer.
2. Explain any two processes involved in the cycling of nitrogen in the environment.
Answer:
1. The circulation of carbon dioxide is important in nature as it helps in maintaining the balance of carbon dioxide and oxygen in the atmosphere. Carbon dioxide is taken up by plants for photosynthesis and oxygen released during photosynthesis is utilised by the plants and animals for respiration.

Hence, it is necessary to maintain the balance of these gases. Carbon dioxide gas gets cycled between the atmosphere and the living organisms. An excess of carbon dioxide in the atmosphere causes global warming due to the greenhouse effect.

2. The two-process involved in the cycling of nitrogen in the environment are nitrogen fixation and ammonification.

(a) Nitrogen fixation in which the atmospheric nitrogen is converted into nitrites and nitrates which are water-soluble and are easily taken up the roots.

(b) Ammonification: Formation of ammonia due to the decomposition of dead organic matter is called as Ammonification.

Question 2.
State the reason for the following:
1. Excess burning of coal causes the greenhouse effect.
2. Soil is a mixture.
3. Temperature ranges from (-190°C -110°C) on the surface of the moon.
Answer:
1. Carbon dioxide gas is released during the burning of fuel like coal and petroleum. Carbon dioxide has a property due to which it allows rays of the Sun to pass through and reach the surface of the Earth but stops the long-wave infra-red radiations to pass through on being re-radiated from the surface of the Earth. Thus, carbon dioxide traps the heat rays of the Sun and causes the greenhouse effect.

2. Soil is a mixture of minerals, organic matter, gases, liquids, and the various organisms that together support life on Earth.

3. The moon does not have an atmosphere like that on the Earth which traps the heat rays of the Sun and keeps its warm. The atmosphere helps in checking rise in temperature during the day and the fall in temperature during night. So, in spite of being at the same distance from the Sun as the Earth, the temperature on moon ranges from (-190°C-110° C).

Question 3.
With the help of the diagram shows the carbon cycle in nature. What are the two ways in which carbon dioxide is fixed in the environment?
Answer:
The carbon cycle in nature can be depicted by the following diagram:

Carbon dioxide is fixed in the atmosphere by the following two ways:
1. Green plants utilise the carbon dioxide and convert it into glucose during photosynthesis.
2. Carbon dioxide dissolved in seawater in the form of carbonates gets used up by marine animals for the formation of their shells.

Question 4.
Sun as a natural factor helps in the formation of soil. Explain.
Answer:
The Sun helps in soil formation in the following ways:
Rocks expand when they get heated by the Sun during the day. During the night, the rocks cool down and contract. This results in the formation of cracks in the rocks as the rate of expansion and contraction are different. The rocks split and break into smaller pieces.

Question 5.
What is the percentage of oxygen in the atmosphere? Name any two compounds of oxygen found in nature. Name any three processes by which oxygen is used up in the atmosphere.
Answer:
The percentage of oxygen in the atmosphere is approximately 21%.
The diatomic form oxygen (O₂) and the triatomic form ozone (O₃) are the two forms in which oxygen is found in nature.
The three processes by which oxygen is used up in the atmosphere are:

• Combustion of fossil fuels.
• Respiration by living organisms.
• Decomposition of organic matter.
• Formation of oxides during fixation and other chemical reactions.

Question 6.
How is the greenhouse effect related to global warming? Explain.
Answer:
The phenomenon in which the incoming sunlight is allowed to pass through the atmosphere but heat radiated back from the planet’s surface is trapped by the gases like carbon dioxide, water vapour and methane present in the atmosphere is called the greenhouse effect.

An increase in the percentage of greenhouse gases like carbon dioxide and methane prevents the escape of heat from the Earth. So, the greenhouse effect is responsible for the increase in average temperature worldwide and is causing global warming. Global warming leads to melting of glaciers and polar ice caps at a faster rate which causes a rise of the sea and other odd climatic changes.

Question 7.
Why is water necessary for the living organisms?
Answer:
Water is necessary for living organisms because:

• All cellular metabolic processes occur in the water medium.
• The transportation of various substances from one part of the body to another occurs in dissolved form in water.
• All the reactions taking place in the cells or in our body occur between substances which are dissolved in water.

Question 8.
How are various biological factors needed for soil formation?
Or
Which symbiotic life forms can grow on stones and help in the formation of soil? Write the model of their action for making soil from rocks.
Answer:
Lichens are the symbiotic association of algae and fungi. Lichens help in the formation of soil. The living organisms like lichens and mosses are the initial colonisers of the rocks which secrete certain chemical substances which dissolve the minerals of rock and cause the gradual weathering of rocks. The rocks get broken down into small, fine particles of soil. So, biological factors play an important role in the formation of soil.

Question 9.
What is topsoil? Mention two factors that decide which plants will thrive on that soil.
Answer:
Topsoil refers to the topmost layer of the soil which contains humus, soil particles and living organisms.
The two factors that decide which plants will thrive on that soil are:

• The humus content and the type of microbes present in the soil.
• The size and texture of soil particles along with the composition of the soil.

Question 10.
What are the causes of soil erosion?
Answer:
The causes of soil erosion are:

1. Large scale deforestation
2. Large scale overgrazing
3. Industrialisation
4. Urbanisation
5. The land left uncultivated for a long time
6. Mining and other human activities which lead to loss of topsoil

Question 11.
Rivers from land, add minerals to seawater. Discuss how.
Answer:
Yes, it is true because water has the ability to dissolve a large number of substances. When the river water flows over the rocks containing soluble minerals, some of the minerals from the rocks get dissolved in the water. These minerals are carried away by the river water into the sea. Thus, the nutrients from the land are carried away by the river into the sea.

Question12.
How can we prevent the loss of topsoil?
Answer:
The loss of the topsoil can be prevented by the following ways:

1. Overgrazing by cattle should be avoided.
2. Large scale afforestation should be done as roots of the plants prevent the soil from getting carried away.
3. Increasing the vegetation cover on the ground reduces the impact of flowing water on soil and prevents it from getting washed away.
4. Contour farming can be done by ploughing the land in furrows across the natural slope of the land to trap water flowing down.
5. Step farming is practised in hilly regions which reduces the flow of water and gives it more time to percolate into the soil.

Question 13.
How is the life of organisms living in water affected when water gets polluted?
Answer:
When the water gets polluted, the life of organisms living in water gets affected in the following ways:

1. The domestic wastewater contains detergents and nutrients which increase the growth of aquatic plants, algae, etc., and reduces the amount of dissolved oxygen in the water body. This adversely affects the aquatic animals as they die due to scarcity of oxygen.
2. The fertilisers, pesticides, etc., which get washed into the water body from the agricultural fields also harm the aquatic organisms.
3. Many disease-causing organisms are also released in the domestic wastewater which acts as a source of many water-borne diseases like cholera.
4. The heated water released directly into the water bodies by some industries can cause the death of aquatic organisms which are not able to tolerate the sudden change in temperature.
5. The heavy metals dissolved in polluted water is also harmful to the living organisms.

Question 14.
During summer, if you go near the lake, you feel relief from the heat, why?
Answer:
We feel relief from the heat when we go near a lake during summer because:
1. The Sunrays heat the land near the lakes more quickly than the water of the lake. The hot air rises up to create a region of low pressure on the land. Evaporation of the water causes cooling of the air above the lake and this cool air flows from the lake towards the region of low pressure on the land. The cool air gives relief to us from the heat.

Question 15.
In the coastal area, wind current moves from the sea towards the land during the day; but during the night
Answer:
During the day, in the coastal regions, the air above the land gets heated faster and the warm air being lighter rises up thereby creating a region of low pressure. The air over the sea then moves towards the area of low pressure. The movement of air from one region to the other creates winds. At night, water cools down slower than the land, so the air above the water would be warmer than the air above land. This causes air over the land to move towards the region of low pressure over water.

Question 16.
Following are a few organisms
(a) lichen
(b) mosses
(c) mango tree
(d) cactus.
Which among the above can grow on stones; and also help in the formation of soil? Write the model of their action for making soil.
Answer:
Lichens and the mosses can grow on stones and help in the formation of soil. The chemical substances secreted by the living organisms like lichens and mosses degrade the rocks and convert them into fine particles of soil. They also cause crevices and cracks in the rocks which help in the colonisation of rocks by bigger plants. The roots of these plants widen the cracks and cause the breakdown of large rocks.

Question 17.
Soil formation is done by both abiotic and biotic factors. List the names of these factors by classifying them as abiotic and biotic?
Answer:
The abiotic factors involved in soil formation are: Sun, water, wind.
The biotic factors involved in soil formation are: lichens, mosses and trees, microorganisms, etc.

Question 18.
All the living organisms are basically made up of C, N, S, P, H and O. How do they enter the living forms? Discuss.
Answer:
Elements like C, N, S, P, H and O enter the living forms through the process of photosynthesis and on getting absorbed from soil by the plants and living organisms.

Question 19.
Why does the percentage of gases like oxygen, nitrogen and carbon dioxide remain almost the same in the atmosphere?
Answer:
The biotic and the abiotic components of the biosphere interact with each other and continuously cycle the elements like nitrogen, oxygen and carbon through their respective cycles called as biogeochemical cycles. This helps to maintain the percentage of these gases almost constant in the atmosphere.

Question 20.
Why does the moon have very cold and very hot temperature variations e.g., from -190°C to 110°C even though it is at the same distance from the Sun as the Earth is?
Answer:
The moon does not have an atmosphere due to which very cold and very hot temperature variations from -190°C to 110°C occur on its surface. The atmosphere helps in maintaining the temperature as it prevents the excessive rise in temperature during daytime and prevents excessive cooling during the night by trapping heat energy of the Sun.

Question 21.
Why do people love to fly kites near the seashore?
Answer:
The wind blows from the sea towards the land during the daytime which helps in flying the kite higher. Also, the wind coming from the sea is cooler which makes the kite flyers feel comfortable. So, people love to fly kites near the seashore.

Question 22.
Why does Mathura refinery pose problems to the Taj Mahal?
Answer:
The harmful gases like sulphur dioxide released from the Mathura oil refinery get mixed with the water vapour present in the air and form acids like sulphuric acid. This acid falls along with the rains in the form of acid rain. The acid present in the acid rain is causing the corrosion of the marble used in the Taj Mahal. The colour (yellowing of marble was caused), as well as the quality of the marble, was getting degraded due to the acid rains. Thus, Mathura refinery posed a problem to the Taj Mahal.

Question 23.
Why do lichens not occur in Delhi whereas they commonly grow in Manali or Darjeeling?
Answer:
Lichens are bio-indicators as they help in assessing the level of pollution in the environment. They are highly sensitive to the gaseous pollutants like sulphur dioxide released from the vehicles and other sources. Delhi has a large number of vehicles and the industries which emit these gases compared to Manali or Darjeeling. So, lichens are unable to grow in Delhi.

Question 24.
Why does water need conservation even though large oceans surround the landmasses?
Answer:
The freshwater resources like river, ponds, lake, etc., are not evenly distributed on the Earth. Most part of the Earth is covered by the oceans and seas which have marine water (salty water) which is not fit for human consumption. So, there is a need to conserve the freshwater resources and the water available to us.

Question 25.
There is a mass mortality of fishes in a pond. What may be the reasons?
Answer:
The mass mortality of fishes in a pond can be the result of one or more of the following factors:

1. Thermal pollution due to the heated water directly released into the water body which harms the organisms that are not able to withstand the sudden change in temperature.
2. The release of heavy metals, poisonous substances like mercury or other harmful chemicals into the waterbody.
3. Blockage of the gills of the fishes by the pollutants or the suspended particles released into the waterbody.
4. Harmful pesticides or chemicals washed into the waterbody from the agricultural fields.
5. Toxic wastes released into the water by the industries.

Question 26.
Lichens are called pioneer colonisers of bare rock. How can they help in the formation of soil?
Answer:
The chemicals released by the lichen cause the gradual weathering of the large particles of rock into smaller fine particles of soil. Thus, they help in the formation of soil.

Question 27.
“Soil is formed by water.” If you agree to this statement then give reasons.
Answer:
Yes, water helps in the formation of soil as it helps in the breakdown of large rocks into fine particles of soil by the following two ways:

1. The water enters the cracks and crevices in the rocks, gets unevenly heated by the Sun and when it expands during freezing in the winter season, the rocks break down in smaller pieces.
2. Also, the fast running water over the surface of the rocks causes weathering of rocks to form soil.

Question 28.
Fertile soil has lots of humus. Why?
Answer:
Fertile soil has a lot of hummus because

1. Soil particles are bound in the form of crumbs by the humus which helps the soil in aeration as well as hydration.
2. Humus contains many kinds of minerals dissolved in it.
3. Growth of the plants is enhanced by the various chemicals present in humus.
4. Soil becomes porous due to humus which facilitates the penetration of roots into the soil.

Question 29.
Why is step farming common in hills?
Answer:
Step farming is practised in hilly regions which reduce the flow of water or the rainwater and gives it more time to percolate into the soil.

Question 30.
Why are root nodules useful for the plants?
Answer:
The plants called legumes to harbour the nitrogen-fixing bacteria like Rhizobium in their roots in the form of root nodules. These bacteria convert the atmospheric nitrogen into nitrites or nitrates which can be assimilated by plants.

Natural Resources Class 9 Extra Questions Long Answer Type

Question 1.
1. Make a neat and labelled sketch of the nitrogen cycle in nature.
2. Describe in brief the role of nitrogen-fixing bacteria and lightning in fixing nitrogen.
Answer:
1. The nitrogen cycle is:

2. The atmospheric nitrogen can be fixed in the following ways:
By nitrogen-fixing bacteria: The nitrogen-fixing bacteria live either in a symbiotic association like the Rhizobium in the root nodules of the legumes or live freely like Azotobacter. The bacteria fix the atmospheric nitrogen into nitrates which are absorbed by the plants in soluble form and assimilated in their body.

By lightning: Lightning has enormous energy which breaks nitrogen molecules and enables their atoms to combine with oxygen present in the air to form nitrogen oxides. These oxides dissolve in rain, form nitrates and are carried to the Earth with the rains.

Question 2.
Explain the role of the atmosphere as a blanket. List the factors deciding the rainfall patterns.
Answer:
The atmosphere is a blanket of air around the Earth which acts as a buffer to prevent the excessive or
sudden rise of temperature during the day and also prevents excessive cooling of the Earth during the night. It slows down the escape of heat into the outer space during the night.

Thus, the atmosphere helps to keep the average temperature of the Earth fairly steady during the day and also during the whole year. The prevailing wind patterns decide the rainfall patterns. The South-West monsoon and the North-East monsoon cause rains in large parts of India.

Question 3.
1. Many municipal corporations are trying water harvesting to improve the availability of water. Give reason.
2. Rainwater sometimes contains traces of acid. Why? Explain in brief.
Answer:
1. The Municipal Corporations are trying water harvesting in order to recharge the underground water reservoirs and the underground water level. This ensures the availability of water during the scarcity of rainfall or water. Rainwater harvesting involves the collection of water from surfaces on which rain falls and stores this water for later use. Generally, the water is collected from the roofs of buildings and stored in rainwater tanks.

2. Combustion of fossil fuels releases oxides of nitrogen (NO₂) and sulphur (SO₂) which dissolve in rainwater to form their respective acids. These acids then fall along with rains and such rain is called acid rain. Due to the presence of such acids, the rainwater sometimes contains traces of acids.

Question 4.
How does the addition of undesirable substances and change in temperature affect water life?
Answer:
Addition of undesirable substances affects the water life in the following ways:

1. Addition of harmful chemicals or metals like mercury, lead, etc., cause poisoning of water bodies and harm aquatic organisms.
2. The pathogens released into the water bodies are the cause of many human diseases like cholera, typhoid, etc.
3. Aquatic organisms are harmed and even killed due to deficiency of oxygen which occurs when the addition of sewage, fertilisers and nutrients in the water body resulting in excessive growth of algae. The algae drain out the oxygen from the water body.

The change in temperature can also affect water life because:

1. The variation in temperature affects the breeding patterns of aquatic animals.
2. The hatching of the eggs is adversely affected due to the changes in the temperature of the water.

Question 5.
What are the various factors or the processes that make soil?
Answer:
Soil is formed due to various physical, chemical and biological processes which result in the breakdown of rocks into fine particles of soil over millions of years. The formation of soil occurs due to factors and processes like Sun, water, wind, living organisms and lichens.

1. Sun: Rocks expand when they get heated by the Sun during the day. During the night, the rocks cool down and contract. This result in the formation of cracks in the rocks as the rate of expansion and contraction are different. The rocks split and break into smaller pieces.

2. Water: Water acts in two ways to break the large rocks into small pieces. Water enters the cracks and crevices in the rocks, gets unevenly heated by the Sun and when it expands during freezing in the winter season, the rocks break down into smaller pieces. Also, the fast running water over the surface of the rocks causes weathering of rocks to form soil.

3. Wind: The winds carry small rocks and sand from one place to another and these strong winds rub against the large rocks to erode them.

4. Living organisms (Lichens): The chemical substances secreted by the living organisms like lichens degrade the rocks and convert them into fine particles of soil.

Question 6.
How do fossil fuels cause air pollution?
Answer:
Fossil fuels like coal and petroleum produce oxides of nitrogen and sulphur on combustion. These gases react with water vapour present in the air to form acids which fall down along with rains on the Earth. Acid rain is very harmful to the plants, animals and the microorganisms present in the soil. Also, the suspended particulate matter released on the burning of fossil fuels cause respiratory problems to human beings and reduces visibility when it forms smog.

Question 7.
What are the causes of water pollution? Discuss how you can contribute in reducing water pollution. Ans. Addition of undesirable and harmful substances in water or the removal of useful substances from water
is referred to as water pollution. It is caused due to:

1. Addition of fertilisers and pesticides washed away from the agricultural field into the nearby water bodies.
2. Disposal of domestic sewage into the waterbody like rivers.
3. The death of many aquatic organisms occurs when hot water from the industries is directly released into the water body. This also reduces the amount of dissolved oxygen in the waterbody.
4.  Washing of the clothes in the waterbody using detergents.
5. Many harmful radioactive substances released from the industries dumped into the waterbody.

Water pollution can be reduced by the following measures:

1. The sewer lines should not be directly connected to the waterbody.
2. Disposal of garbage and wastes into the waterbody should not be allowed.
3. Toxic compounds released from the industries should not be dumped in the water bodies.
4. Detergents increase the nutrient content of water which is harmful to aquatic organisms as the amount of dissolved oxygen gets reduced in water due to excessive algal growth. Therefore water containing detergents should not be allowed to run off into water bodies.
5. Trees should be planted near the banks of the river to prevent soil erosion which leads to siltation in the water bodies.

Question 8.
A motor car, with its glass totally closed, is parked directly under the Sun. The inside temperature of the car rises very high. Explain why.
Answer:
Glass has a property due to which it allows the radiations of the Sun to pass through and enter the car. Infrared radiations also enter the car along with other radiations. Glass is transparent to infrared. radiation from the Sun having smaller wavelength but opaque to longer wavelength radiations that are emitted by the interior of the car.

The infrared radiations get re-radiated by upholstery and other inner parts of the car but cannot pass out of the glass like the other radiations. So, the heat trapped inside raises the temperature inside the car.

Question 9.
Justify “Dust is a pollutant”.
Answer:
Dust can be considered as a pollutant because:

1. Suspended particles are present in the dust which can enter the respiratory systems of the organisms and can cause asthma, bronchitis, allergies or other respiratory diseases.
2. When dust falls on the leaf surface, it can cause blocking of the stomata which adversely affects the process of photosynthesis and plant growth.
3. Many heavy metals and toxic compounds are present in the dust which can harm living organisms.
4. Dust can be harmful to the eyes of the organism as irritation and reddening of eyes can be caused due to it.

Question 10.
Explain the role of the Sun in the formation of soil.
Answer:
The Sun helps in soil formation in the following ways:
Rocks expand when they get heated by the Sun during the day. During the night, the rocks cool down and contract. This result in the formation of cracks in the rocks as the rate of expansion and contraction are different. The rocks split and break into smaller pieces.

Question 11.
Carbon dioxide is necessary for plants. Why do we consider it as a pollutant?
Answer:
Carbon dioxide is necessary for the plants, as it is utilised during the process of photosynthesis. It acts as a raw material for photosynthesis and helps in maintaining the temperature on the Earth. If the concentration of carbon dioxide increases in the atmosphere above a certain level, it traps more heat of the Sun because it is a greenhouse gas.

This ultimately results in an increase in the average temperature on Earth and causes global warming. Due to higher temperatures, the polar ice caps, glaciers and the snow of mountains melt faster. This can lead to floods and an increase in seawater level. So, carbon dioxide is considered a pollutant.

Natural Resources Class 9 Extra Questions HOTS

Question 1.
What is the fate of the glucose molecules formed in photosynthesis?
Answer:
The glucose molecules formed during photosynthesis are either stored in the form of starch in the green plants or get transported in the form of sucrose to the various parts of the plant. Glucose is also utilised by the plants during respiration to obtain energy.

Question 2.
What is the likely outcome if all the oxygen in the environment gets converted into ozone?
Answer:
If all the oxygen in the environment gets converted into ozone it will be harmful to the living organisms as ozone adversely affects the living organisms and would eventually kill them.

Question 3.
We are lucky that ozone is not stable near the Earth’s surface. Why?
Answer:
The ozone present in the lower atmosphere is called ‘bad ozone’ as it adversely affects the living organisms, corrodes metals, acts as a greenhouse gas and creates respiratory problems in animals. So, we are lucky that ozone is not stable near the Earth’s surface as it gets converted into oxygen or the various oxides.

Question 4.
1. Nitrogen-fixing bacteria are usually found only in the root nodules of leguminous plants. Why?
2. Name a non-leguminous plant which has nitrogen-fixing bacteria in root nodules and the microbe present in it.
Answer:
1. The nitrogen-fixing bacteria are usually found only in the leguminous plants as the roots of the leguminous plants provide shelter and the specific conditions required for such bacteria. The bacteria like Rhizobium live in symbiotic association with the roots of leguminous plants.

2.  Alnus is a non-leguminous plant which has a nitrogen-fixing bacteria called Frankia in its root nodules.

Question 5.
What will be the consequences if all the decomposers are removed from the Earth?
Answer:
Decomposers play a vital role in the recycling of various nutrients. The recycling of the nutrients would be hindered in the absence of decomposers. They also help in the decomposition of dead plants, animals and organic matter. In the absence of decomposers, the Earth would get covered by the remains of such organisms and it would become difficult for the organisms to survive on Earth.

Question 6.
Excessive use of pesticides in the fields can adversely affect the fishes living in the nearby ponds. How?
Answer:

• The pesticides used in the fields can get washed into the nearby water bodies by the rains and flowing water.
• These pesticides cause a phenomenon called biological magnification which adversely affects the fishes of the pond.

Question 7.
Excess use of fertilisers in the field is not advisable to the farmers. Give reasons.
Answer:
Excess use of fertilisers increases the food production for a short term but in the long term, it is not advisable to the farmers because
1. Excess use of fertilisers increases the salinity of the soil and reduces its fertility.
2. The fertilisers can get washed away into the nearby ponds where they cause excessive growth of algae due to nutrient enrichment. This depletes the dissolved oxygen from the water body and harms the other aquatic organisms.

Question 8.
The public transport like buses and the autos have shifted to CNG instead of petrol or diesel in Delhi. Why?
Answer:
The public transport like the buses and the autos have shifted to CNG instead of petrol or diesel in Delhi because the gases released from these vehicles cause a lot of pollution and harms the environment in following ways:

• The oxides of nitrogen and sulphur released from the vehicles result in acid rains which is harmful to the living organisms.
• The harmful gases from the exhaust result in several problems like asthma, respiratory disorders, cancer, etc.

Question 9.
Discharge of sewage into the water body decreases the amount of oxygen dissolved in water. How?
Answer:
The sewage water consists of a lot of organic matter which is decomposed by the microorganisms present in the water body. The microorganisms multiply at a rapid rate and consume a lot of dissolved oxygen in order to decompose the organic matter. This reduces the amount of dissolved oxygen in the water.

Question 10.
What will be the result if all the plants get eliminated from the Earth?
Answer:
Plants perform photosynthesis and release oxygen during the process which is used by the other organisms for survival. If all the plants become extinct, eventually all the oxygen requiring living organisms including us will get eliminated from the Earth.

Natural Resources Class 9 Extra Questions Value Based (VBQs)

Question 1.
Vijay is the son of a rich businessman. He lives in a very big house. He always insists and reminds the family members to switch off lights, fans, TVs, etc., of rooms when there is no one in the room, so that use of electricity is minimum. He realises that power generation on a large scale in thermal power plants produces a lot of carbon dioxide and fly ash.
Read the given passage and answer the following questions:

1. How is carbon dioxide responsible for global warming?
2. What measures will you take to reduce levels of carbon dioxide?
3. What values are displayed by Vijay in his action and thoughts?

Answer:
1. Carbon dioxide has a property due to which it allows rays of Sun to pass through and reach the surface of the Earth but stops the rays from being re-radiated from the surface of Earth. The heat of the Sun rays gets trapped by carbon dioxide in this way and causes global warming.
2. The levels of carbon dioxide can be reduced in the atmosphere by increasing the efficiency of engines of vehicles, large scale afforestation, reducing the emission of carbon dioxide from the industries and using alternative sources of energy in place of fossil fuels.
3. The values shown by Vijay are a concern for the environment, intelligence, awareness and scientific attitude.

Question 2.
Due to the establishment of a petroleum refinery near the city, many people started suffering from respiratory problems and the marble used in their houses turned yellow. A survey carried out by Arpit and his colleagues attributed this to the gases released from the refinery. They consulted the Government agencies and suggested to shift the refinery away from the city.
Based on the above, answer the following questions:

1. What can be the reason behind the yellowing of marble?
2. What are the various harmful effects of air pollution?
3. What values are depicted by the efforts of Arpit and his colleagues?

Answer:

1. The oxides of nitrogen and sulphur released from the petroleum refinery dissolve in rainwater to form acids and fall on the Earth. When this acid rain falls on marble it causes yellowing of the marble.
2. The other harmful effects of air pollution are:
   (a) Formation of smog which harms living organisms.
   (b) Respiratory problems, bronchitis, asthma, cancer, etc.
3. The values depicted by Arpit and his colleagues are scientific aptitude, care for the environment and a responsible citizen.

Question 3.
Amrita saw that the farmers of her village use excessive fertilisers and pesticides on their crop. She searched the internet for the effect of such action on the environment. She came to know that their excessive use is harmful to the environment. She talked to the Head of the village and the farmers were motivated to use fertilisers and pesticides judiciously. They were also motivated to practice organic farming for better crop yield.
Based on the above, answer the following questions:
1. How is excessive use of fertilisers and pesticides harmful to the environment?
2. What is organic farming?
3. What values are shown by Amrita in solving the problem?
Answer:
1. The fertilisers and the pesticides get washed away into the nearby water bodies with rainwater or the flowing water.
Excess use of fertilisers causes uncontrolled growth of algae in water bodies which depletes the dissolved oxygen in the water and causes death other aquatic organisms. Excess use of pesticides causes biological magnification which leads to death of many fishes in the water bodies.
2. Organic farming is a method of crop production in which no chemical pesticides or fertilisers are used during the cultivation of crops.
3. The values shown by Amrita are curiosity, inquisitive nature, care for the environment and scientific attitude.

Question 4.
Zeenat and her sister were very happy when their father brought home a new refrigerator. She saw a sticker pasted on the refrigerator which read ‘CFC free’. She asked her father about it. Her father told her that the compounds called CFC are the cause of the ozone hole and so they are not used in the refrigerators to save our environment.
Read the above passage and answer the following:

1.  What is ozone and why is it important?
2. What are CFCs and why are they harmful?
3. What values are shown by Zeenat and her father?

Answer:

1. Ozone is a triatomic molecule of oxygen with formula 03. It traps the harmful rays of the Sun and protects the living organisms.
2. The CFCs are the carbon compounds having both fluorine and chlorine which are very stable and not degraded by any biological process. They persist in the atmosphere and degrade the ozone layer.
3. The quality shown by Zeenat is a curious nature. Her father shows the values of concern for the environment, patience and imparting right knowledge to children.

Question 5.
A farmer came for a consultation with Rajni who worked as ‘Kisan Mitra’ in the village. He told her that he was growing leguminous crop in the field, so what will by the right amount of nitrogenous fertilisers required in his field? Rajni told him that since he was growing leguminous crops in the field, he does not require adding more nitrogenous fertilisers in the field. She further suggested him to grow the leguminous crop alternately with maize or wheat.
Based on the above, answer the following questions:
1. Why did Rajni advise the farmer not to add more nitrogenous fertilisers in his field?
2. Why did she suggest him to grow leguminous crop alternately with maize or wheat?
3. What values are shown by Rajni?
Answer:
1. Rajni advised the farmer not to add more nitrogenous fertilisers as the leguminous plants which the farmer had sown in the field have root nodules which contain nitrogen-fixing bacteria. These nitrogen-fixing bacteria fix the atmospheric nitrogen and give it to the plant, so no additional nitrogen-containing fertilisers are required in the field.

2. Rajni advised the farmer to grow leguminous crop alternately with maize or wheat as the nutrients are taken up by the wheat or maize from the soil will be restored by the nitrogen-fixing bacteria present in the root nodules of the leguminous crop. In this way, the fertility of the soil will be restored and enriched again by the leguminous crop. The process is called crop rotation.

3. The values shown by Rajni are patience, knowledge, proper decision making, scientific aptitude, concern for the environment

In this page, we are providing The Fundamental Unit of Life Class 9 Extra Questions and Answers Science Chapter 5 pdf download. NCERT Extra Questions for Class 9 Science Chapter 5 The Fundamental Unit of Life with Answers will help to score more marks in your CBSE Board Exams. https://ncertmcq.com/extra-questions-for-class-9-science/

Class 9 Science Chapter 5 Extra Questions and Answers The Fundamental Unit of Life

Extra Questions for Class 9 Science Chapter 5 The Fundamental Unit of Life with Answers Solutions

The Fundamental Unit of Life Class 9 Extra Questions Very Short Answer Type

The Fundamental Unit Of Life Class 9 Extra Questions And Answers Question 1.
What process is involved in the movement of O₂ in and out of the cell?
Answer:
Diffusion.

Fundamental Unit Of Life Class 9 Extra Questions Question 2.
Which process is involved in the movement of water from outside into the cell?
Answer:
Osmosis.

Extra Questions For Class 9 Science Chapter 5 With Answers Question 3.
Mention the process by which CO₂ and water move in and out of the cell.
Answer:
Movement of CO₂ occurs by diffusion whereas that of water occurs by osmosis.

Class 9 Science Chapter 5 Extra Questions And Answers Question 4.
Who discovered cells in living organisms? Give an example of a unicellular organism.
Answer:
A.V. Leeuwenhoek observed the.cells in living organisms. Example of a unicellular organism is Amoeba, Paramoecium, etc.

Class 9 Fundamental Unit Of Life Extra Questions Question 5.
Give two examples of prokaryotic organisms.
Answer:
All the bacteria and cyanobacteria are prokaryotic. Example: Nostoc, Oscillatoria, etc.

Fundamental Unit Of Life Extra Questions Question 6.
Name the plastid which stores starch, oils and protein granules.
Answer:
Leucoplast

The Fundamental Unit Of Life Extra Questions Question 7.
List the constituents of plasma membrane.
Answer:
The plasma membrane is composed of lipids and proteins.

Class 9 Science Ch 5 Extra Questions Question 8.
Where do lipids and proteins constituting the cell membrane get synthesised?
Answer:
The lipids are synthesised in smooth endoplasmic reticulum (SER) and the proteins are synthesised in the rough endoplasmic reticulum (RER).

Chapter 5 Science Class 9 Extra Questions Question 9.
Name two unicellular organisms.
Answer:
Amoeba and Paramoecium are unicellular organisms.

Ch 5 Science Class 9 Extra Questions Question 10.
Name the process by which unicellular freshwater organisms and most plant cells tend to . gain water.
Answer:
Endosmosis.

The Fundamental Unit of Life Class 9 Extra Questions Short Answer Type 1

The Fundamental Unit Of Life Class 9 Extra Questions And Answers Ncert Question 1.
Why is plasma membrane called selectively permeable membrane?
Answer:
Plasma membrane is called selectively permeable because it prevents the entry of some substances and allows the entry and exit of only some substances.

Class 9 Chapter 5 Science Extra Questions Question 2.
Define osmosis.
Answer:
The spontaneous movement of water molecules from a region of its high concentration to the region of its low concentration through a selectively permeable membrane is called osmosis.

Ncert Class 9 Science Chapter 5 Extra Questions Pdf Question 3.
What is membrane biogenesis?
Answer:
Some proteins and lipids made by smooth endoplasmic reticulum (SER) help in building the cell membrane of the cell and this process of making of plasma membrane is known as membrane biogenesis.

Ncert Class 9 Science Chapter 5 Extra Questions Question 4.
Why are mitochondria are referred to as strange organelles?
Answer:
Mitochondria are referred to as strange organelles as they have their own DNA and ribosomes so and can make some of their own proteins.

Class 9 Ch 5 Science Extra Questions Question 5.
What is the function of Golgi body?
Answer:
The functions of Golgi body are: storage, modification and packaging of products in vesicles and the formation of lysosomes.

Class 9 Science Chapter 5 Extra Questions Question 6.
(i) In what form do mitochondria release energy? Write its full form.
(ii) The inner membrane of mitochondria is deeply folded. What is the advantage of these folds?
Answer:
(i) The energy is released by mitochondria in form of ATP. Full form of ATP is adenosine triphosphate.

(ii) The folds present on the inner membrane of mitochondria help to provide a large surface area for the ATP generation reactions.

Class 9 The Fundamental Unit Of Life Extra Questions Question 7.
Give three differences between plasma membrane and the cell wall.
Answer:
Plasma Membrane:

• It is the outermost covering of the cell which separates the contents of the cell from its external environment.
• It is mainly composed of lipids and proteins.
• It is living, thin and elastic.

Cell Wall:

• It is a rigid outer covering which lies outside the plasma membrane.
• It is made of cellulose which provides structural strength to plants.
• It is non-living and rigid.

Extra Questions Of Fundamental Unit Of Life Question 8.
Differentiate between nucleus and nucleoid.
Answer:
Nucleus:

• It has a well defined nuclear membrane around it.
• It has chromatin network and contains more than one chromosome.

Nucleoid:

• It lacks a nuclear membrane.
• It has a single chromosome only.

Extra Questions For Class 9 Science Chapter 5 Question 9.
Write two statements to show that lysosomes are called as suicidal bags of the cell.
Answer:
Lysosomes are called as the suicidal bags of the cell as:

1. They contain hydrolytic enzymes which can breakdown the organic material.
2. If the cell gets damaged during disturbance in cellular metabolism, the lysosomes may burst and its enzymes digest their own cell.

Question 10.
Describe the structure of mitochondria with special reference to its membrane covering.
Answer:
Mitochondrion is a double-membrane structure whose outer membrane is very porous while the inner membrane is deeply folded to form cristae. Cristae are folds which create a large surface area for ATP- generating chemical reactions.

The Fundamental Unit of Life Class 9 Extra Questions Short Answer Type 2

Question 1.
Describe an activity to demonstrate endosmosis and exosmosis. Draw a diagram also.
Answer:
Put dried raisins or apricots in plain water and leave them for some time. Then place them into a concentrated solution of sugar or salt. You will observe the following:

(a) Each of the raisins or apricots gains water and swells when placed in water.
Reason: The raisins or apricots swell up as water moves inside them from outside because the water concentration is less inside the cell as compared to the solution outside. Hence, water moves inside the cell by endosmosis.

(b) However, when placed in the concentrated solution they lose water, and consequently shrink.
Reason: The raisins or apricots shrink as water moves outside from them because the water concentration is more inside the cell as compared to the solution outside. Hence, water moves out of the cell by exosmosis.

Question 2.
Differentiate between diffusion and osmosis. Write any two examples where a living organism uses osmosis to absorb water.
Answer:
Diffusion – The movement of a substance from a region of its high concentration to the region of its low concentration is called diffusion.

Osmosis – The spontaneous movement of water molecules from a region of its high concentration to the region of its low concentration through a selectively permeable membrane is called osmosis.

Examples where a living organism uses osmosis to absorb water are:

• Roots of plants absorb water by osmosis.
• Unicellular organisms like Amoeba absorb water by osmosis.

Question 3.
Differentiate between a prokaryotic and eukaryotic cell.
Answer:
Prokaryotic cell:

• Organisms whose cells lack a well defined nuclear membrane.
• They lack membrane bound cell organelles.
• Size is generally small (1-10 pm).
• Have a single chromosome.

Eukaryotic cell:

• Organisms with cells having a well defined nuclear membrane.
• They have membrane bound cell organelles.
• Size is generally large (5-100 pm).
• Have more than one chromosome.

Question 4.
Which organisms are called as the (i) powerhouse of the cell (ii) suicide bags of the cell (iii) kitchen of the cell?
Answer:

• Mitochondria
• Lysosomes
• Chloroplasts

Question 5.
(a) What would happen to the life of the cell if there was no Golgi apparatus?
(b) Which cell organelle detoxifies poisons and drugs in the liver of vertebrates?
Answer:
(a) If there was no golgi apparatus, then the following processes carried out by it would get affected:

• The storage, modification and packaging of products in vesicles.
• The packaging and dispatch of the material synthesised near the ER to various targets inside and outside the cell.
• The formation of lysosomes.
• The formation of cell plate during cell division.

So, in the absence of the Golgi apparatus, most of the functions of the cell would get disrupted.

(b) Smooth endoplasmic reticulum helps to detoxify poisons and drugs in the liver of vertebrates.

Question 6.
What are the functions of the Golgi apparatus?
Answer:
The Golgi apparatus is an important cell organelle as it performs several functions in the cell.

1. Its functions include the storage, modification and packaging of products in vesicles.
2. Golgi apparatus packages and dispatches the material synthesised near the ER to various targets inside and outside the cell.
3. It is also involved in the formation of lysosomes.

Question 7.
What types of enzymes are present in the lysosomes? What is their function? Which cell organelle manufactures these enzymes?
Answer:
Lysosomes are membrane-bound sacs filled with hydrolytic and digestive enzymes. They help to keep the cell clean by digesting any foreign material as well as worn-out cell organelles. Rough endoplasmic reticulum (RER) manufactures these enzymes.

Question 8.
What are chromoplasts and leucoplasts? Give an example of chromoplast which has green pigment.
Answer:
The coloured plastids which have pigments of different colours are called chromoplasts. The colourless plastids which help to store starch, oils or protein granules are called leucoplasts. The green coloured plastid is called chloroplast and it contains a green coloured pigment called chlorophyll.

Question 9.
Write the functions of:
(i) Inner membrane of mitochondria
(ii) Nucleus of the cell
(iii) Ribosomes present in active cells.
Answer:
The functions are:
(i) Inner membrane of mitochondria are the site for the formation of ATP.

(ii) Nucleus of the cell are the control centre of the cell as it controls all the activities of the cell, plays a central role in cellular reproduction and contains DNA which helps to transfer the genetic information from parents to their offsprings.

(iii) Ribosomes present in active cells are the sites for protein synthesis.

Question 10.
What are the different types of endoplasmic reticulum? Write the functions of each.
Answer:
There are two types of endoplasmic reticulum – Rough endoplasmic reticulum and smooth endoplasmic reticulum. The functions of these are:

Rough endoplasmic reticulum – It looks rough as it has particles called ribosomes attached to its surface. Ribosomes are the site of protein synthesis.

Smooth endoplasmic reticulum:

• It helps in the manufacture of fat molecules, or lipids, important for cell function.
• Some proteins and lipids made by SER help in building the cell membrane and this process is known as membrane biogenesis.
• Helps in detoxifying many poisons and drugs in the liver cells of the group of vertebrates.

Question 11.
Draw a neat and labelled diagram of a typical prokaryotic cell.
Answer:

Question 12.
Why do plant cells possess large sized vacuole?
Answer:
Plant cells possess large sized vacuoles as the vacuoles help to store many important substances. They contain cell sap that gives turgidity and rigidity to the plant cell.

Question 13.
Describe the structural features of cell membrane and cell wall. Why is cell membrane called selectively permeable membrane?
Answer:
Cell wall:

• It is a rigid outer covering which lies outside the plasma membrane.
• It is made of cellulose which provides structural strength to plants.
• The shrinkage or contraction of the contents of the cell away from the cell wall when a living plant cell loses water through osmosis is known as plasmolysis.

Cell membrane:

• It is the outermost covering of the cell.
• It separates the contents of the cell from its external environment.
• It is mainly composed of lipids and proteins.

The cell membrane is called selectively permeable as it permits the entry and exit of only some materials in and out of the cell. It prevents the movement of the contents of the cell out of the cell.

Question 14.
Explain in detail what do you know about the structure of the nucleus.
Answer:
The nucleus was discovered by Robert Brown in 1831. The structure and the features of nucleus are:

• It is a dark coloured, spherical or oval, dot-like structure near the centre of each cell.
• It is the control centre of the cell as it controls all the activities of the cell.
• It has a double layered covering called nuclear membrane.
• The nuclear membrane has pores which allow the transfer of materials from inside the nucleus to the cytoplasm.
• The nucleus plays a central role in cellular reproduction (process by which a single cell divides and forms two new cells).
• Nucleus along with the environment directs the chemical activities of the cell to determine the way the cell will develop and the form it will exhibit at maturity.
• Nuclear region of the cell may be poorly defined due to the absence of a nuclear membrane in some organisms like bacteria. Such an undefined nuclear region containing only nucleic acids is called a nucleoid.

Question 15.
Differentiate between rough and smooth endoplasmic reticulum. How is endoplasmic reticulum important for membrane biogenesis?
Answer:
The differences between smooth endoplasmic reticulum and the rough endoplasmic reticulum are:

Smooth Endoplasmic Reticulum (SER):

• SER looks smooth as it does not have ribosomal particles on the surface.
• SER helps in the manufacture of lipids and fat molecules and also in detoxifying many poisons and drugs in the liver cells of the group of vertebrates.

Rough Endoplasmic Reticulum (RER):

• RER appears rough as it has particles of ribosomes on the surface.
• Ribosomes present on RER are the sites of protein synthesis.

Ribosomes are the sites of protein synthesis in all active cells. Endoplasmic reticulum helps in transporting these proteins to various places. Some proteins and lipids made by SER help in building the cell membrane, this process is known as membrane biogenesis.

Question 16.
Describe the phenomenon of membrane biogenesis. Give one function of ER.
Answer:
Some proteins and lipids made by SER help in building the cell membrane and this process is known as membrane biogenesis.

ER serves as channels for the transport of materials (especially proteins) between various regions of the cytoplasm or between the cytoplasm and the nucleus. It also functions as a cytoplasmic framework providing a surface for some of the biochemical activities of the cell.

Question 17.
(i) Why are lysosomes known as ‘scavengers of the cell’?
(ii) Lysosomes are self-destructive. (True/False). Give reason.
Answer:
(i) The lysosomes are waste disposal system of the cell as they remove the debris and help to keep the cell clean by digesting any foreign material as well as worn-out cell organelles. Thus, they are known as the ‘scavengers of the cell’.

(ii) It is true that the lysosomes are self-destructive. They contain digestive enzymes. If the cell gets damaged during disturbance in cellular metabolism, the lysosomes may burst and its enzymes digest their own cell.

Question 18.
Name the organelle of the cell, which has membrane bound sac filled with powerful digestive enzymes. Write any four common functions it performs inside the cell.
Answer:
Lysosome is a membrane bound sac filled with powerful digestive enzymes.

The functions of lysosomes are:

• They are waste disposal system of the cell as they help to keep the cell clean by digesting any foreign material as well as worn-out cell organelles.
• They have digestive enzymes which are capable of breaking down all organic materials.
• If any disturbance occurs in the cellular metabolism or the cell gets damaged, the lysosomes burst open and its digestive enzymes digest all the contents of the cell. So, they are also called as the ‘suicide bags’ of the cell.
• During starvation they digest the food contents of the cell and provide energy to the cell.

Question 19.
State reasons for the following:
(i) Mitochondria are known as the powerhouse of the cell.
(ii) Plastids are able to make their own protein.
(iii) Plant cell shrinks when kept in hypertonic solution.
Answer:
(i) Mitochondria are known as the powerhouse of the cell as they are the site of storage of ATP which helps to provide energy for all the activities of the cell.

(ii) Plastids are able to make their own protein as they have their own DNA and ribosomes.

(iii) Hypertonic solution has a lower concentration of water than the cell. Due to this, the water moves out of the plant cell by exosmosis and results in shrinkage of the plant cell.

Question 20.
List the specific functions of the following:
(i) Endoplasmic reticulum
(ii) Golgi apparatus
(iii) Lysosomes
(iv) Plastids
(v) Mitochondria
(vi) Vacuoles.
Answer:
The specific functions are:
(i) Endoplasmic reticulum: Site of protein synthesis.

(ii) Golgi apparatus: Storage, modification and packaging of products in vesicles.

(iii) Lysosomes: Waste disposal system of the cell as they help to keep the cell clean by digesting any foreign material as well as worn-out cell organelles.

(iv) Plastids: Green coloured plastids are the site of photosynthesis.

(v) Mitochondria: They are called the powerhouse of the cell as they store energy required for the activities of the cell in the form of ATP.

(vi) Vacuoles: Provide turgidity and rigidity to the cell in plant cells. They also help in digestion of food and expulsion of excess water and waste from the cell in unicellular organisms like Amoeba.

Question 21.
Which types of plastids stores starch, oil and proteins?
Answer:
The leucoplasts help to store starch, oil and proteins in the amyloplasts, elaioplasts and aleuroplasts respectively.

Question 22.
How many membranes are present in mitochondria? Give the characteristic features of these membranes. What is the advantage of such features?
Answer:
Mitochondrion is a double-membrane structure whose outer membrane is very porous while the inner membrane is deeply folded to form cristae. The porous membrane helps in getting oxygen and food. Cristae present on the inner membrane are the folds which create a large surface area for ATP- generating chemical reactions.

Question 23.
Why are lysosomes known as ‘suicide-bags’ of a cell?
Answer:
Lysosomes are also known as the ‘suicide bags’ of a cell because if the cell gets damaged during disturbance in cellular metabolism, the lysosomes may burst and its enzymes digest their own cell.

Question 24.
Do you agree that “A cell is a building unit of an organism”. If yes, explain why?
Answer:
Yes, a cell is the building unit or the fundamental unit of an organism as the cells get organised to form tissues which in turn get organised into organs and further into organ system which organise to form an organism. It can be represented as:
Cell → tissue → organ → organ system organism

Question 25.
Why does the skin of your finger shrink when you wash clothes for a long time?
Answer:
The skin of our finger shrinks when we wash clothes for a long time because soap solution is a hypertonic solution i.e., very concentrated solution, so water moves out of our finger cells by the process of osmosis (called as exosmosis).

Question 26.
Why is endocytosis found in animals only?
Answer:
The plant cells have a rigid structure due to the presence of cell wall around their cell membrane whereas in the animals the cell membrane does not have a cell wall. So, endocytosis can occur only in the animal cells.

Question 27
A person takes concentrated solution of salt, after sometime, he starts vomiting. What is the phenomenon responsible for such situation? Explain.
Answer:
A concentrated solution of salt is hypertonic solution and causes dehydration. Water moves out of the cells and exosmosis in the parts of stomach and intestine make the person feel uncomfortable. Excessive dehydration results in anti-peristalsis due to which person starts vomiting.

Question 28.
Name any cell organelle which is non membranous.
Answer:
Ribosomes are non membranous organelles.

Question 29.
We eat food composed of all the nutrients like carbohydrates, proteins, fats, vitamins, minerals and water. After digestion, these are absorbed in the form of glucose, amino acids, fatty acids, glycerol, etc. What mechanisms are involved in absorption of digested food and water?
Answer:
Absorption of the nutrients takes place by diffusion and that of water occurs by the process of osmosis.

Question 30.
If you are provided with some vegetables to cook. You generally add salt into the vegetables during cooking process. After adding salt, vegetables release water. What mechanism is responsible for this?
Answer:
Adding salt into vegetables creates a hypertonic medium around them which results in exosmosis. Exosmosis causes release of water form vegetables.

Question 31.
If cells of onion peel and RBC are separately kept in hypotonic solution, what among the following will take place? Explain the reason for your answer.
(a) Both the cells will swell.
(b) RBC will burst easily while cells of onion peel will resist the bursting to some extent.
(c) a and b both are correct.
(d) RBC and onion peel cells will behave similarly.
Answer:
(b) RBC will burst easily while cells of onion peel will resist the bursting to some extent. This happens because the cells of onion peel have cell wall which prevents them from bursting. The RBC, being animal cells are devoid of cell wall and burst easily in hypotonic solution.

Question 32.
Bacteria do not have chloroplast but some bacteria are photo-autotrophic in nature and perform photosynthesis. Which part of bacterial cell performs this?
Answer:
The photo-autotrophic bacteria have small vesicles associated with plasma membrane which help in the process of photosynthesis.

Question 33.
Match the following A and B

Answer:
(a) (iv)
(b) (v)
(c) (iii)
(d) (i)
(e) (ii)

Question 34.
Write the name of different plant parts in which chromoplast, chloroplast and leucoplast are present. Chromoplasts are present in the flower and fruit.
Answer:
Chloroplasts are present in the leaves of the plant. Leucoplasts are present in the root of the plant.

Question 35.
Name the organelles which show the analogy written as under
(a) Transporting channels of the cell _______
(b) Powerhouse of the cell _______
(c) Packaging and dispatching unit of the cell _______
(d) Digestive bag of the cell _______
(e) Storage sacs of the cell _______
(f) Kitchen of the cell _______
(g) Control room of the cell _______
Answer:
(a) Transporting channels of the cell _______ Endoplasmic reticulum
(b) Powerhouse of the cell _______ Mitochondria
(c) Packaging and dispatching unit of the cell _______ Golgi body
(d) Digestive bag of the cell _______ Lysosome
(e) Storage sacs of the cell _______ Vacuole
(f) Kitchen of the cell _______ Chloroplast
(g) Control room of the cell _______ Nucleus

Question 36.
How is a bacterial cell different from an onion peel cell?
Answer:
Bacterial cell is a prokaryote so, they are smaller in size, their nucleus does not have a well defined nuclear membrane, possess a single chromosome and the cell is devoid of any cell organelles. Onion peel cell is an eukaryotic cell which is comparatively bigger in size, nucleus has a well defined nuclear membrane, possess more than one chromosome and have well defined cell organelles.

Question 37.
How do substances like carbon dioxide (CO₂) and water (H₂O) move in and out of the cell?
Answer:
The movement of carbon dioxide occurs by the process of diffusion in and out of the cell whereas the movement of water in and out of the cell occurs by the process of osmosis.

Question 38.
How does Amoeba obtain its food?
Answer:
Amoeba takes in food with the help of finger like extensions called pseudopodia by the process called endocytosis. Pseudopodia help to engulf the food which gets enclosed in a food vacuole. The complex particles of the food get broken down into simpler substances inside the food vacuole and diffuse into the cytoplasm of Amoeba. The undigested food particles are removed from the cell by exocytosis.

Question 39.
Name the two organelles in a plant cell that contain their own genetic material and ribosomes.
Answer:
Mitochondria and plastids (e.g. chloroplasts) contain their own genetic material and ribosomes.

Question 40.
Why are lysosomes also known as “scavengers of the cells”?
Answer:
The lysosomes are waste disposal system of the cell as they remove the debris and help to keep the cell clean by digesting any foreign material as well as worn-out cell organelles.

Question 41.
Which cell organelle controls most of the activities of the cell?
Answer:
Nucleus is the control centre of the cell and controls most of the activities of the cell.

Question 42.
Which kind of plastid is more common in
(a) roots of the plant
(b) leaves of the plant
(c) flowers and fruits
Answer:
The plastid that is more common in
(a) roots of the plant is leucoplast.
(b) leaves of the plant is chloroplast.
(c) flowers and fruits is chromoplast.

Question 43.
Why do plant cells possess large sized vacuole?
Answer:
The plant cells possess large sized vacuoles as the vacuoles help to store many important substances. They contain cell sap that gives turgidity and rigidity to the plant cell.

Question 44.
How are chromatin, chromatid and chromosomes related to each other?
Answer:
The chromatin material forms chromatids, i.e., chromatids are made up of chromatin. The chromosomes are made up of thread like structures called as chromatids.

Question 45.
What are the consequences of the following conditions?
(a) A cell containing higher water concentration than the surrounding medium
(b) A cell having low water concentration than the surrounding medium.
(c) A cell having equal water concentration to its surrounding medium.
Answer:
The consequences of the following conditions are:
(a) A cell containing higher water concentration than the surrounding medium will undergo exosmosis.

(b) A cell having low water concentration than the surrounding medium will undergo endosmosis.

(c) A cell having equal water concentration to its surrounding medium will not be affected as there won’t be any net movement of water into or outside the cell.

The Fundamental Unit of Life Class 9 Extra Questions Long Answer Type

Question 1.
Distinguish between hypotonic solution, isotonic solution and hypertonic solution.
Answer:
The differences between the three kinds of solutions are:

Question 2.
Describe the roles played by lysosomes. Why are they termed as suicidal bags? How do they perform their function?
Answer:
Roles played by lysosomes are:
(i) They are waste disposal system of the cell as they help to keep the cell clean by digesting any foreign material as well as worn-out cell organelles.

(ii) Lysosomes have powerful digestive enzymes capable of breaking down all organic materials. Lysosomes are also known as the ‘suicide bags’ of a cell because if the cell gets damaged during disturbance in cellular metabolism, the lysosomes may burst and its enzymes digest their own cell. They perform this function as they are membrane-bound sacs filled with hydrolytic and digestive enzymes made by rough endoplasmic reticulum (RER).

Question 3.
(a) Name the organelle which provides turgidity and rigidity to the plant cell. Name any two substances which are present in it.
(b) How are they useful in unicellular organisms?
Answer:
(a) The organelle which provides turgidity and rigidity to the plant cell is the large central vacuole which is filled with cell sap. The substances present in it are amino acids, sugars, various organic acids and some proteins.

(b ) They are very useful for the unicellular organisms in the form of food vacuole and contractile vacuole which perform the following functions:

Food vacuole found in Amoeba contains the food items that the Amoeba has consumed.
Contractile vacuole found in some unicellular organisms help in expelling excess water and some wastes from the cell.

Question 4.
What will happen if:
(i) Ribosomes are removed from the cell?
(ii) Golgi apparatus is removed from the cell?
(iii) Plasma membrane ruptures?
Answer:
(i) If ribosomes are removed from the cell, protein synthesis will not take place, enzymes will not be formed and ultimately death of cell will occur.

(ii) If golgi apparatus is removed from the cell, storage, modification and the packaging of substances in vesicles will not occur and lysosomes will not be formed.

(iii) Plasma membrane is a selectively permeable membrane, so in its absence, the entry and exit of the substances will not be regulated, contents of the cell will leak out and the cell will die.

Question 5.
Draw a plant cell and label the parts which
(a) determines the function and development of the cell
(b) package materials coming, from the endoplasmic reticulum
(c) provides resistance to microbes to withstand hypotonic external media without bursting
(d) is site for many biochemical reactions necessary to sustain life
(e) is a fluid contained inside the nucleus
Answer:
(a) Nucleus
(b) Golgi apparatus
(c) Cell wall
(d) Cytoplasm
(e) Nucleoplasm

Question 6.
Illustrate only a plant cell as seen under electron microscope. How is it different from an animal cell?
Answer:

Plant Cell:

• Cell wall is present.
• Plastids are present.
• A large central vacuole is present.
• Centrioles are absent.

Animal Cell:

• Cell wall is absent.
• Plastids are absent.
• Vacuoles are either absent or very small.
• Centrioles are present.

Question 7.
Draw a neat labelled diagram of an animal cell.
Answer:

Question 8.
Draw a well labelled diagram of an eukaryotic nucleus. How is it different from a nucleoid?
Answer:

It is different from a nucleoid as it is a membrane bound organelle.

Question 9.
Differentiate between rough and smooth endoplasmic reticulum. How is endoplasmic reticulum important for membrane biogenesis?
Answer:
Smooth Endoplasmic Reticulum (SER):

• SER looks smooth as it does not have ribosomal particles on its surface.
• SER helps in the manufacture of lipids and fat molecules and also in detoxifying many poisons and drugs in the liver cells of the group of vertebrates.

Rough Endoplasmic Reticulum (RER):

• RER appears rough as it has particles of ribosome on its surface.
• Ribosomes present on RER are the sites of protein synthesis.

Ribosomes are the sites of protein synthesis in all active cells. Endoplasmic reticulum helps in transporting these proteins to various places. Some proteins and lipids made by SER help in building the cell membrane, this process is known as membrane biogenesis.

Question 10.
In brief state what happens when
(a) dry apricots are left for sometime in pure water and later transferred to sugar solution?
(b) a red blood cell is kept in concentrated saline solution?
(c) the plasma-membrane of a cell breaks down?
(d) Rhoeo leaves are boiled in water first and then a drop of sugar syrup is put on it?
(e) golgi apparatus is removed from the cell?
Answer:
(a) If dry apricots are left for sometime in pure water they swell up due to endosmosis and later when they are transferred to sugar solution exosmosis occurs and they shrink.

(b) If a red blood cell is kept in concentrated saline solution it will lose water and shrink.

(c) If the plasma-membrane of a cell breaks down, the cell will die.

(d) If Rhoeo leaves are boiled in water first and then a drop of sugar syrup is put on it, no plasmolysis occurs as the cells get killed on boiling.

(e) If the golgi apparatus is removed from the cell, all sorts of vesicle formation in the cell get stopped.

Question 11.
Draw a neat diagram of plant cell and label any three parts which differentiate it from animal cell.
Answer:
The plant cells have chloroplast, large central vacuole and the cell wall which are not present in animal cells.

The Fundamental Unit of Life Class 9 Extra Questions HOTS

Question 1.
Unicellular organisms like Amoeba and Paramoecium survive as a single cell. How?
Answer:
In Amoeba and Paramoecium all the activities like digestion, absorption, assimilation, etc., which are necessary for life are carried out by a single cell. This enables them to survive even as a single cell.

Question 2.
Explain how cell walls permit the cells of fungi to withstand very dilute external media without bursting.
Answer:
The fungal cells swell up in very dilute external media as they take in water by the process of endosmosis. The plasma membrane of the cell exerts pressure on the cell wall and the cell wall also exerts an equal pressure on the membrane which helps to prevent the cell from bursting.

Question 3.
Give the roles of the following:
(i) Lipids and proteins of plasma membrane
(ii) Cellulose in the cell wall
(iii) Flexible nature of the cell membrane
(iv) Hydrolytic enzymes of lysosomes
(v) Ribosomes present on the RER
Answer:
The roles are:
(i) Lipids and proteins of plasma membrane: Provide flexibility to cell membrane and make it selectively permeable in nature.

(ii) Cellulose in the cell wall: Provides structural strength to the plants and prevents bursting of the cell when the cell swells in a hypotonic solution.

(iii) Flexible nature of the cell membrane: It helps organisms like Amoeba to engulf food by endocytosis.

(iv) Hydrolytic enzymes of lysosomes: Helps in the process of cell digestion and act as ‘scavengers of cell’.

(v) Ribosomes present on the RER: Are the site of protein synthesis.

Question 4.
Which cell organelle will play a major role when a cell is damaged due to disturbance in cellular metabolism? How?
Answer:
Lysosomes will play a major role when a cell is damaged due to disturbance in cellular metabolism. The lysosomes burst open and its hydrolytic digestive enzymes digest their own cell contents. Thus, lysosomes are also called as the ‘suicidal bags’.

Question 5.
What will be the effect on the cell when:
(a) The cell is placed in a medium having lower water concentration.
(b) The cell is placed in a medium having higher water concentration.
(c) The cell is placed in a medium having water concentration which is equal to that inside the cell.
Answer:
The consequences of the following conditions are:
(a) The cell having low water concentration than the surrounding medium will undergo endosmosis.
(b) The cell containing higher water concentration than the surrounding medium will undergo exosmosis.
(c) The cell having equal water concentration to its surrounding medium will not be affected as there won’t be any net movement of water into or outside the cell.

The Fundamental Unit of Life Class 9 Extra Questions Value Based (VBQs)

Question 1.
Rajni was told by his teacher that cell is the structural and fundamental unit of life. She asked her teacher to give reasons to support her statement. She felt very happy when her teacher showed her the slide of onion peel with the help of a microscope. She was able to identify the various parts of the cells visible in the slide.
(i) Why is the cell called the structural and functional unit of life?
(ii) With the help of a suitable diagram show the cells observed in onion peel and label them.
(iii) What values are shown by Rajni?
Answer:
(i) The body of all living organisms is composed of one or more cells, so cell is called the structural unit of life. Also, the various life processes like digestion, respiration, excretion, etc., are performed by the cells, so the cell is called the functional unit of life.

(ii) The cells of onion peel are shown in the diagram below.

(iii) Values shown by Rajni are curiosity, scientific temper, knowledge and sincerity towards her work.

 

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Class 9 Science Chapter 13 Extra Questions and Answers Why Do we Fall Ill

Extra Questions for Class 9 Science Chapter 13 Why Do we Fall Ill with Answers Solutions

Why Do we Fall Ill Class 9 Extra Questions Very Short Answer Type

Why Do We Fall Ill Class 9 Extra Questions Question 1.
What are infectious or communicable diseases?
Answer:
The diseases which are caused by infectious agents are called as infectious diseases as they can spread from one person to another through some medium or by direct contact.
Example: Pneumonia, common cold, tuberculosis, etc.

Why Do We Fall Ill Extra Questions Question 2.
What are congenital diseases?
Answer:
The diseases which are present in a person since birth are called congenital diseases.
Example: colour blindness.

Why Do We Fall Ill Class 9 Extra Questions Pdf Question 3.
Give one local and one general effect of the inflammation process.
Answer:
Swelling or pain is a local effect. Fever or headache is a general effect.

Class 9 Why Do We Fall Ill Extra Questions Question 4.
Name the organism causing the following diseases:
(a) Kala-azar
(b) Sleeping sickness
Answer:
Kala-azar is caused by Leishmania; Sleeping sickness is caused by Trypanosoma.

Class 9 Science Chapter 13 Extra Questions And Answers Question 5.
It was diagnosed that a patient has lost the power of fighting any infection.
(i) Name the disease the patient is suffering from.
(ii) Name the pathogen responsible for the disease.
Answer:
(i) AIDS.
(iii) HIV is the causative organism of AIDS. [HIV-Human immunodeficiency virus]

Extra Questions Of Why Do We Fall Ill Question 6.
What is immunity?
Answer:
The ability of the body of a person to fight against the disease causing organisms is called immunity. Name any disease that can be prevented by using vaccines.

Class 9 Science Ch 13 Extra Questions Question 7.
The diseases which can be prevented by using vaccines.
Answer:
The diseases which can be prevented by using vaccines are polio, small pox, diphtheria, tetanus, measles, etc.

Extra Questions Of Why Do We Fall Ill Class 9 Question 8.
What are principles of treatment of a disease?
Answer:
The principles of treatment are:

• reducing the effects of the disease.
• to kill the cause of the disease.

Extra Questions On Why Do We Fall Ill Question 9.
How do children in many parts of India get immune to hepatitis-A by the time they are five year old?
Answer:
The children become immune to hepatitis A virus as they are exposed to hepatitis A virus present in the water they drink.

Ch 13 Science Class 9 Extra Questions Question 10.
Name the causative organisms of tuberculosis and cholera.
Answer:
Tuberculosis: Caused by bacterium called as Mycobacterium tuberculosis.
Cholera is caused by a bacterium called as Vibrio cholera

Why Do we Fall Ill Class 9 Extra Questions Short Answer Type 1

Extra Questions Why Do We Fall Ill Question 1.
What are the differences between acute and chronic diseases?
Answer:
Acute disease:

• The disease which lasts for only very short periods of time is called acute disease.
• They get over soon and do not get much time to affect the health more adversely. Example: Common cold

Chronic disease:

• The disease which can last for a long time, even as much as a lifetime is called chronic disease.
• They have a long-term effect on the health of a person. Example: Elephantiasis

Class 9 Science Why Do We Fall Ill Extra Questions Question 2.
What is a pandemic disease? Give one example.
Answer:
The disease which affects the health of human population all over the world is called a pandemic disease. For example, AIDS.

Class 9 Biology Chapter 13 Extra Questions Question 3.
Mention the symptoms because of which you will visit a doctor and why?
Answer:
High fever, headache, tiredness, loose motion, cough and cold, loss of appetite and body weight are some of the symptoms for which we will visit a doctor because the doctor would be able to ascertain the disease caused on the basis of the symptoms produced and give medication accordingly.

Class 9 Biology Why Do We Fall Ill Extra Questions Question 4.
Why is DPT called triple antigen?
Answer:
DPT is called as triple antigen as it affects three antigens to produce the antibodies against them. The diseases are: Diphtheria, Pertussis and Tetanus.

Extra Questions From Why Do We Fall Ill Question 5.
What are the symptoms shown by a person if the
(i) lungs get infected?
(ii) stomach is infected?
Answer:
(i) Cough, breathlessness, tiredness are the symptoms produced if the lungs of a person get affected by a disease.

(ii) Loose motion, vomiting and stomachache are the symptoms produced when the stomach of a person gets affected by a disease.

Question 6.
“In our country majority of children are already immune to hepatitis A without giving its vaccine to them.” Justify this statement giving reasons.
Answer:
Majority of the children are already exposed to the hepatitis A virus by the time they are five years old because the water which the children generally drink contains the hepatitis A virus. The immune system thus helps to develop immunity against the virus.

Question 7.
List any four factors that must be taken care of by an individual for keeping good health.
Answer:
The four factors which must be taken care by an individual for keeping good health are:

• Proper nourishing balanced diet
• Clean and hygienic environment
• Good social environment
• Proper sanitation and cleanliness

Question 8.
Why are antibiotics effective against bacteria?
Answer:
Antibiotics block the biochemical pathways of the bacteria which inhibit their growth and kill them. For example: Penicillin blocks the pathway involved in the synthesis of cell wall which protects the bacteria. This inhibits their growth and kills them.

Question 9.
Influenza or common cold spreads faster and is difficult to control. Explain.
Answer:
Influenza and common cold are infectious diseases which are spread through air, so it becomes difficult to control them.

Question 10.
Why are overcrowded and poorly ventilated areas, major factors in the spread of air-borne diseases?
Answer:
In poorly ventilated and overcrowded areas, the little droplets containing air-borne microbes thrown by an infected person on coughing or sneezing, can be easily inhaled by a healthy person standing close by. This can start a new infection in the healthy person. Hence, such areas are major factors in the spread of air-borne diseases.

Question 11.
(a) Name the organ into which the malarial parasite enters after a mosquito bite.
(b) Give two examples of air-borne diseases.
Answer:
(a) The malarial parasite enters the liver of the healthy person after mosquito bite.
(b) Common cold and pneumonia are some air-borne diseases.

Question 12.
What are non-infectious diseases? Give two examples of non-infectious diseases.
Answer:
The diseases which do not spread from one person to the other person in the community are called as non-infectious diseases. They are caused due to internal factors.
Example: Cancer, high blood pressure, diabetes, etc.

Question 13.
Identify infectious and non-infectious diseases from the diseases given below: Tuberculosis, goitre, marasmus and typhoid.
Answer:

• Infectious diseases are tuberculosis and typhoid.
• Non-infectious diseases are goitre and marasmus.

Question 14.
Write the symptoms and diseases associated with the following:
(a) when microbes attack the lungs
(b) when the virus enters the liver
Answer:
(a) Tuberculosis may occur when microbes attack the lungs. The symptoms would be persistent cough, blood in sputum, prolonged low fever.

(b) Jaundice may occur when the virus enters the liver. The symptoms would be headache, high fever, loss of appetite and dark yellow coloured urine.

Question 15.
Why does a person suffering from the disease HIV-AIDS dies even due to small infection?
Answer:
The HIV damages the immune system of the person suffering from AIDS. Due to this the body of the person is unable to fight against even the small infections. The immune system of the person becomes very weak and ultimately leads to the death of the person due to several infections.

Why Do we Fall Ill Class 9 Extra Questions Short Answer Type 2

Question 1.
(a) Define disease.
(b) Explain briefly the two groups of diseases.
Or
Differentiate between infectious and non-infectious diseases.
Answer:
(a) Disease refers to any condition that disturbs the normal functioning of the living organism. It is a condition of disturbed ease when an individual feels uncomfortable.

(b) The two groups of diseases are infectious diseases and the non-infectious diseases.
Infectious diseases:

• These diseases are caused by infectious agents. These can spread from one person to another through some medium or by direct contact.
• Example: Pneumonia, common cold, tuberculosis, etc.

Non-infectious diseases:

• These do not spread form one person to the other person in the community. They are caused due to
• internal factors.
  Example: Cancer, high blood pressure, diabetes, etc.

Question 2.
What are acute and chronic diseases? Which one of the two is more harmful and why? Give an example in support of your answer.
Answer:
Acute disease:

• The disease which lasts for only very short periods of time is called acute disease.
• They get over soon and do not get much time to affect the health more adversely. Example: Common cold

Chronic disease:

• The disease which can last for a long time, even as much as a lifetime is called chronic disease.
• They have a long-term effect on the health of a person. Example: Elephantiasis

Chronic diseases are more harmful as they persist for a long time and thus adversely affect the general health of the person suffering from them.

Question 3.
Giving reasons, justify that it is difficult to prepare antiviral medicines than antibiotics.
Or
Why is it difficult to prepare anti-viral medicines than antibiotics?
Or
Explain why antibiotics do not work against viruses but work against many group of bacteria.
Answer:
Antibiotics are the chemicals which usually block the biochemical pathways of the bacteria. This inhibits their growth and kills them. But, the viruses do not have their own biochemical pathways as present in the bacteria. Viruses use the host machinery to multiply themselves. So, it becomes difficult to prepare anti-viral vaccines in order to inhibit their growth.

Question 4.
How do diseases spread through air? Name two such diseases.
Answer:
The diseases spread through air when little droplets thrown out by an infected person who sneezes or coughs are inhaled by a healthy person. This results in a new infection in the healthy person.
Example: Common cold, pneumonia and tuberculosis.

Question 5.
Why does a person who has suffered once from small pox cannot suffer with it again?
Answer:
The immune system of our body responds against the disease causing small pox virus when it encounters it for the first time. This interaction is slower and less vigorous, but the immune system remembers the virus specifically. Whenever the immune system encounters the virus after this first response, the interaction is more vigorous and the immune system completely eliminates the virus. Thus, the small pox virus is not able to affect the person who has suffered from it once.

Question 6.
How is the principle of immunisation implemented for eliminating polio?
Answer:
The polio vaccine which is administered to the children in the form of polio drops contains the weakened polio causing pathogen which is not able to cause the disease but enables the immune system of the child to produce antibodies against the polio virus. Subsequent encounter of the child to the polio virus activates the immune system which kills the polio virus and protects the immunised child from the disease. Thus, principle of immunisation helps in eliminating polio.

Question 7.
Give the cause and the remedy of:
(a) Hepatitis
(b) AIDS
(c) Malaria
Answer:

Question 8.
“Being disease free is not the same as being healthy.” Explain the statement by giving an example.
Answer:
Disease refers to any condition that disturbs the normal functioning of the living organism. It is a condition of disturbed ease when an individual feels uncomfortable. Being disease-free is a concept which applies to individual sufferer.

Even a disease free person can be considered as having a poor health if the person is unfit in terms of social and mental health. So, health is a concept which applies to societies and communities.

For example: a disease free person suffering from mental stress and tension cannot be considered as healthy.

Question 9.
A person was bitten by a stray dog. After some days his nature gets irritated, he started fearing water.
(a) Name the disease.
(b) Is there any vaccine available?
(c) Is there any plan of your local authority for the control of this disease?
Answer:
(a) The disease caused due to bite of a stray dog is rabies.
(b) Yes, anti-rabies vaccine is available.
(c) Local authorities have planned immunisation of the stray dogs against the disease.

Question 10.
It was diagnosed that the body of a patient had lost his power of fighting any infection. Name the disease the patient was suffering from. Which microbe is responsible for this disease? Give two ways by which it spreads from one person to another.
Answer:
The disease is called AIDS (Acquired immunodeficiency syndrome) and the microbe which is responsible for the disease is a virus called HIV (Human immunodeficiency virus). The ways to control the disease are:

• Creating awareness among people regarding the modes of spread of the disease.
• Use of disposable syringes in hospitals and clinics.
• Avoiding sexual contact with multiple partners.

Question 11.
Give two examples for each of the following:
(a) Acute diseases
(b) Chronic diseases
(c) Infectious diseases
(d) Non-infectious diseases
Answer:
(a) Acute diseases: Common cold, eye flu
(b) Chronic diseases: Tuberculosis (TB), asthma
(c) Infectious diseases: Chicken pox, small pox
(d) Non-infectious diseases: Goitre, Cancer

Question 12.
Name two diseases caused by Protozoans. What are their causal organisms.
Answer:
Malaria is caused by Plasmodium and Kala-azar caused by Leishmania Symptoms of malaria are: high fever and shaking chills that can range from moderate to severe, profuse sweating, headache, nausea, vomiting, etc. Symptoms of Kala-azar are breathing difficulty, recurrent fever and skin sores.

Question 13.
Which bacterium causes peptic ulcers? Who discovered the above pathogen for the first time?
Answer:
Heliobacterium pylori cause peptic ulcers. This pathogen was discovered for the first time by Marshall and Warren.

Question 14.
What is an antibiotic? Give two examples.
Answer:
The chemicals secreted by some microorganisms which can kill the bacteria and other disease causing pathogens are called antibiotic. Example: Penicillin, Streptomycin

Question 15.
Fill in the blanks
(a) Pneumonia is an example of ________ disease.
(b) Many skin diseases are caused by ________
(c) Antibiotics commonly block biochemical pathways important for the growth of ________
(d) Living organisms carrying the infecting agents from one person to another are called ________
Answer:
(a) Communicable
(b) Fungi
(c) Bacteria
(d) Vector

Question 16.
Name the target organs for the following diseases
(a) Hepatitis targets ________
(b) Fits or unconsciousness targets ________
(c) Pneumonia targets ________
(d) Fungal disease targets ________
Answer:
(a) Liver
(b) Brain
(c) Lungs
(d) Skin

Question 17.
Who discovered Vaccine’ for the first time? Name two diseases which can be prevented by using vaccines.
Answer:
Edward Jenner discovered vaccine for the first time. Polio, small pox, typhoid, etc. can be prevented by vaccines.

Question 18.
Fill in the blanks:
(a) ________ disease continues for many days and causes effect the on body.
(b) ________ disease continues for a few days and causes short term effect on the body.
(c) ________ is defined as physical, mental and social well-being and comfort.
(d) Common cold is an ________ disease.
(e) Many skin diseases are caused by ________
Answer:
(a) Chronic, long-term
(b) Acute
(c) Health
(d) Infectious
(e) Fungi

Question 19.
Classify the following diseases as infectious or non-infectious.
(a) AIDS
(b) Tuberculosis
(c) Cholera
(d) High blood pressure
(e) Heart disease
(f) Pneumonia
(g) Cancer
Answer:
(a) infectious
(b) infectious
(c) infectious
(d) non-infectious
(e) non-infectious
(f) infectious
(g) non-infectious

Question 20.
Name any two groups of microorganisms from which antibiotics can be extracted.
Answer:
Bacteria and fungi are the microorganisms from which antibiotics can be extracted.

Question 21.
Name any three diseases transmitted through vectors.
Answer:
Filariasis, Dengue, Chikungunya, Malaria, Kala-azar

Why Do we Fall Ill Class 9 Extra Questions Long Answer Type

Question 1.
(a) Give definition of health.
(b) State and explain in brief the four major factors which cause disease.
Answer:
(a) ‘Health’ is defined as a state of physical, emotional, mental and social well being of a person.
(b) The four factors whose non availability or absence can cause disease are:
(i) Proper nourishing food: If the person does not get proper nourishing food and a balanced diet, then disease may affect the person.

(ii) Proper hygienic conditions and cleanliness: If the surroundings are not hygienic and the public cleanliness is ignored in a society, then the individuals living there become more prone to diseases.

(iii) Good social conditions: The society in which the person lives should cater towards a healthy mind set of the members of the society. A bad social environment makes the individuals of the society develop an unhealthy attitude.

(iv) Good economic conditions: Poverty is a major cause of diseases and poor economic conditions increase the chances of spread of diseases in the society due to inadequate food and unhygienic conditions.

Question 2.
(a) Doctors diagnosed that Radha was suffering from HIV-AIDS. List any two methods by which she might have come in contact with the disease. Name the organ affected by this disease.
(b) Why antibiotics cannot be used for its treatment? Justify your answer.
Answer:
(a) AIDS can spread by four ways: Sexual contact, Transfusion of AIDS infected blood, use of infected syringe and from an infected mother to her baby during pregnancy or through breast feeding.

(b) Antibiotics block the biochemical pathways of the microorganism in order to inhibit their growth and kill them. But, the viruses do not employ such biochemical pathways of their own. They utilise the host machinery to multiply themselves. So, antibiotics cannot be used for the treatment of the viral diseases like AIDS.

Question 3.
(a) If a person is suffering from jaundice, name the mode of its transmission and the organ affected by the disease.
(b) List one general mode of prevention of jaundice.
(c) It has been observed that despite the availability of the vaccine of Hepatitis A in the market, it may not be necessary to be given to children by the time they are 5 years old. Why?
Answer:
(a) Mode of transmission of Jaundice: Contaminated water Organ affected by Jaundice: Liver

(b) Access to pure drinking water can prevent jaundice.

(c) Most of the children of India are already exposed to the hepatitis A virus through the drinking water and their immune system helps to develop immunity against the disease by the time they are five years old. So, it is not necessary to give them the hepatitis A vaccine.

Question 4.
Give an account of malaria, giving its causative agent, symptoms and control measures.
Answer:
Malaria is a protozoan disease caused by Plasmodium species. It gets transmitted by a vector called as the female Anopheles mosquito. The symptoms of malaria are high fever and body ache. The patient feels chills and shivering at regular time intervals. The disease can be controlled by eliminating the breeding grounds of mosquitoes, using mosquito nets or mosquito repellents at home, taking a dose of quinine medicine as prescribed by the doctor.

Question 5.
(a) Name two air-borne diseases. How does the disease causing microbes spread through air?
(b) How does HIV virus spread from a patient to a healthy person?
(c) How does the immune system of our body function?
Answer:
(a) Common cold, tuberculosis, pneumonia are some air-borne infections. They spread from one person to another when an infected person releases droplets into air while coughing or sneezing and these droplets get inhaled by a healthy person standing close by. The microbes start a new infection in the healthy person.

(b) HIV can spread by the following ways: Sexual contact, transfusion of AIDS infected blood, from an infected mother to her baby during pregnancy or through breast feeding, use of infected syringe.

(c) The immune system gets activated on encountering a disease causing microbe or on infection and recruits many cells to the affected tissue by a process called as inflammation. This results in pain, swelling, fever, etc., but ultimately it results in killing the disease causing microbe and prevent spread of infection.

Question 6.
(a) Discuss briefly the principle of immunisation.
(b) Mention any two diseases that can be prevented by immunisation.
Answer:
(a) The process by which immunity or resistance to a disease is developed in an individual by administration of biological preparations called vaccines is known as immunisation. In this process, a harmless or dead pathogen is introduced in the body of the organism by vaccination. The immune system of the organism gets activated and produces antibodies against the pathogen to kill it.

These antibodies remain in the memory of the immune system of the individual and in the case of any subsequent infection by the same microbe, these antibodies act quickly and more vigorously to kill the microbe. In this way, the microbe is not able to infect the person and the person gets immunised against the disease.

(b) Two diseases prevented by immunisation are: Measles and polio. Some other diseases which can be prevented by vaccination are diphtheria, pertusis, whooping cough, hepatitis, tetanus, etc.

Question 7.
Explain giving reasons
(а) Balanced diet is necessary for maintaining healthy body.
(b) Health of an organism depends upon the surrounding environmental conditions.
(c) Our surrounding area should be free of stagnant water.
(d) Social harmony and good economic conditions are necessary for good health.
Answer:
(a) Balanced diet provides raw materials and energy in appropriate amount needed for the proper growth and development of the body. It contains the nutrients like the protein, carbohydrates, fats, minerals etc., in the right amount which helps in the proper growth and functions. This ensures a good health of the individual.

(b) The physical, mental and the social well being of a person is affected by the surrounding environmental conditions. Since, these factors determine the health of a person, we can say that the health of a person depends on the environmental conditions. For example, Unhygienic surroundings as breeding grounds for disease causing organisms and their vectors can harm our health.

(c) Stagnant water is a source of many water-borne diseases and acts as breeding place for many insect vectors which can cause diseases in human beings. So, our surrounding area should be free of stagnant water.

(d) Social harmony ensures that the mental tensions and problems do not surround a person and friendly relations are maintained among the individuals of the society. They strive for the growth and well being of each other and thus better health is maintained in such environment and surroundings. Better economic conditions enable a person to invest more to attain good health by eating nutritive food, ensure protection from diseases, get better medical facilities, etc. So, health of a person is better maintained if economic conditions are good.

Question 8.
What is a disease? How many types of diseases have you studied? Give examples.
Answer:
Any condition that disturbs the normal functioning of the organism or its organs is called a disease. Diseases can be classified as acute, chronic, infectious, non-infectious, etc. The diseases which are for short duration are called acute whereas the diseases which persist for a long time are called chronic diseases, example common cold (acute) and tuberculosis (chronic).

The diseases which can be transmitted from one person to another are called infectious diseases whereas the ones which cannot be transmitted are called non-infectious diseases, example cancer and goitre respectively.

Question 9.
What do you mean by disease symptoms? Explain giving two examples.
Answer:
The physical disturbances or the visual changes which indicate the existence of a disease are called the symptoms of the disease.
Example:

• High fever and chills is a symptom of malaria.
• Appearance of lesions on the skin is a symptom of chickenpox.

Question 10.
Why is the immune system essential for our health?
Answer:
Immune system is essential as it helps our body to fight against disease causing microbes. It protects our body by secreting chemicals called antibodies or other substances which protect us from harmful microbes.

Question 11.
What precautions will you take to justify “prevention is better than cure”?
Answer:
The precautions which can be taken to protect ourselves from the disease are:

• Maintaining personal hygiene as well as clean surroundings.
• Being aware about diseases, their symptqms and the organism which causes then.
• Eating a balanced diet.
• Timely vaccination and regular medical, check-up.

Question 12.
Why do some children fall ill more frequently than others living in the same locality?
Answer:
The reasons due to which some children fall ill more frequently than others living in the same locality can be:

• Poor and inefficient immune system.
• Unhealthy food habits and not taking balanced diet.
• Not maintaining personal hygiene.

Question 13.
Why are antibiotics not effective for viral disease?
Answer:
The mode of action of the antibiotics is blocking the biosynthetic pathways of the bacteria and other microbes. However, viruses do not have such biochemical pathways or have very few biochemical mechanisms of their own, hence viruses are unaffected by antibiotics.

Question 14.
Becoming exposed to or infected with an infectious microbe does not necessarily mean developing noticeable disease. Explain.
Answer:
Becoming exposed to or infected with an infectious microbe does not necessarily mean developing noticeable disease because the immune system becomes active when it encounters a pathogen. If the immune system of the organism is able to ward off the disease causing microbe, then the disease will not occur and the person will remain disease-free. So, a strong immune system can ensure that we do not suffer from diseases even if we are exposed to infectious microbes.

Question 15.
Give any four factors necessary for a person to be healthy.
Answer:
The four factors necessary for a person to be healthy are:

• Proper nourishment and a balanced diet which help to provide a strong immune system.
• Maintaining personal hygiene to protect ourselves from infectious microbes.
• Timely vaccination against various diseases.
• Maintaining community hygiene and clean surroundings will to prevent the incidence of waterborne and the air-borne diseases.

Question 16.
Why is AIDS considered to be a ‘Syndrome’ and not a disease?
Answer:
The causative organism of AIDS is a virus called the HIV which gets transmitted through sexual contact, transfusion of contaminated blood, intravenous syringes used by drug addicts and from a mother suffering with AIDS to her child, spread to lymph nodes all over the body. The virus attacks the immune system of the organism and makes it so weak that it cannot fight against even the minor infections. Due to this even a small cold can develop into pneumonia or minor stomach infection may lead to severe diarrhoea and blood loss in stools.

Ultimately the immune system becomes very weak and leads to the death of the person suffering from AIDS. Many diseases simultaneously develop in such a person, so there is no specific disease symptom but a number of symptoms occur in the person. This group of symptoms are called as ‘syndrome’. So, AIDS is not a disease, it is a syndrome.

Why Do we Fall Ill Class 9 Extra Questions HOTS

Question 1.
The symptoms seen in a patient are high fever, constipation and stomach pain. A doctor wants to confirm whether the patient is suffering from Amoebiasis or typhoid. How can the doctor confirm it?
Answer:
The doctor can advise the patient to get a widal test done which helps to confirm the presence of typhoid causing microorganism in the body. If typhoid is ruled out then the patient is most likely to suffer from Amoebiasis.

Question 2.
Name the disease:
(a) that spreads by sexual contact but not by casual contact like handshake.
(b) that can be caused by virus, bacteria or protozoa.
(c) that can be caused due to bite of stray dog.
Answer:
(a) AIDS
(b) Diarrhoea
(c) Rabies

Question 3.
A mother who had suffered from chicken pox in her childhood, is now taking care of her child, who is suffering from the same disease. What are the chances of her mother having chicken pox? Explain.
Answer:
The mother will not suffer from chicken pox as she has become immune to chicken pox. During the first infection, her immune system develops antibodies against chicken pox. These antibodies respond with more vigour during the next infection, eliminate the microbe and thus prevent the person from the disease.

Question 4.
Name the disease:
(a) in which the liver of the person is the target.
(b) in which saliva of the infected animal spreads infection.
(c) against which BCG vaccine is given.
(d) for which widal test is done.
(e) in which sexual contact spreads the disease but not the physical contact in form of handshakes or hugging.
Answer:
(a) Jaundice and hepatitis
(b) Rabies
(c) Tuberculosis
(d) Typhoid
(e) AIDS

Question 5.
The immune system of a patient has been damaged by a virus. What is the probable disease which would have led to this effect on the immune system? What are the ways by which the pathogen would have been transferred into the individual?
Answer:
The disease is most likely to be AIDS caused by the HIV virus which damages the immune system of the person.

AIDS can be spread in four ways: Sexual contact, transfusion of AIDS infected blood, from an infected i mother to her baby during pregnancy or through breast feeding.

Question 6.
A patient bitten by a stray animal complained of excessive salivation, restlessness and a fear of water. What can be the probable disease and its cause? How can such disease be treated or controlled?
Answer:
The patient is probably suffering from rabies caused by the rabies virus. The disease can be controlled by ensuring proper vaccination of stray animals like dogs. The disease can be treated by timely administration of anti rabies vaccine.

Question 7.
A patient went to a doctor and complained of having a persistent cough, blood in sputum, breathlessness and loss of body weight. Name the disease and the causative microbe. How is the disease transmitted? Which vaccine is given to develop resistance against the disease?
Answer:
The disease from which the patient is suffering is Tuberculosis (T.B.) and the causative microbe is . a bacteria called Mycobacterium tuberculosis.. The disease gets transmitted when a healthy person inhales the droplets released by an infected person on coughing, sneezing or while talking. The vaccine i called BCG is given to develop resistance against the disease.

Question 8.
A child was suffering from loose motions, frequent vomiting, feeling of nausea and watery diarrhoea which led to an excessive loss of fluids from his body. Name the disease and its causative microbe. What measures, can be taken to treat this disease? How can one avoid getting infected by the disease?
Answer:
The person is infected with disease called cholera which is caused by a virus called Vibrio cholerae. The measures which can be taken for treatment of the disease are: Giving ORS-Oral rehydration solution to the patient and giving antibiotics prescribed by the doctor. The disease can be avoided by eating clean and hygienic food and timely immunisation against the disease.

Why Do we Fall Ill Class 9 Extra Questions Value Based (VBQs)

Question 1.
An HIV infected employee was dismissed from service by the employer. The colleagues of the employee in the office intervened and convinced the boss of the company to reinstate the services of the employee as HIV is not transmitted by mere physical contact. They told the employer that such person should not be made a victim of social stigma on contracting the disease.
(i) Name the disease which the employee was suffering from.
(ii) How does the disease get transmitted from one person to another?
(iii) What values are shown by the colleagues of the employee?
Answer:
(i) AIDS: Acquired immunodeficiency syndrome.

(ii) The disease gets transmitted by four ways:
(a) Sex with multiple partners.
(b) Transfusion of HIV contaminated blood.
(c) Use of HIV contaminated syringe.
(d) From infected mother to her child at the time of delivery of the baby.

(iii) The values shown by the colleague of the employee are: awareness, helpfulness, empathy and knowledge about their rights.

Question 2.
Rohit and’ Mayank are roommates in the hostel. Mayank is an avid reader of science magazines and articles. Mayank immediately took Rohit to a doctor when Rohit complained of tiredness, nausea, vomiting and pale eyes. What is the probable disease Rohit was suffering from? Name the causative microbe. What values are shown by Mayank?
Answer:
The symptoms of Rohit show that he was suffering from Jaundice. The microbe which causes the disease is virus. The values shown by Mayank are awareness, scientific temper, concern for others and helpful nature.

Question 3.
The parents of a new bom child were afraid to take their child for vaccination as someone told them that the vaccine contains harmful germs. However, when they consulted Dr. Shweta, she listened to them patiently and then cleared their doubts about vaccines. She told them that the vaccines only contain dead germs or inactivated germs which do not cause the disease. How do the dead germs in vaccines protect from diseases? What are the values shown by Dr. Shweta?
Answer:
The dead or the inactivated germs in the vaccines stimulate our immune system to develop antibodies against the disease causing microbes present in the vaccine and store the antibodies for action during any subsequent infection. In this way the vaccines provide immunity to the person against the disease. The values shown by Dr. Shweta are concern for others, helpfulness and patience.

Question 4.
Megha’s told her that he had been feeling tired, breathless, had persistent cough and blood was coming out in his sputum. She told him that these are symptoms of an infectious disease and advised him to consult a doctor. She also took him for diagnostic tests prescribed by the doctor. The helps was diagnosed as suffering from an infectious disease. He took the medicines prescribed by the doctor and got cured of the disease.
(i) Name the most likely disease and microbe from which the help suffered?
(ii) How does the disease get transmitted?
(iii) What are the values depicted by Megha?
Answer:
(i) The disease is most likely Tuberculosis caused by bacteria.

(ii) The disease gets transmitted when a healthy person inhales the droplets released into air by an infected person while coughing or sneezing.

(iii) Megha shows a helpful nature, scientific attitude, concern for others and sympathetic nature.

Question 5.
The municipality of an area advised the residents of the area to eliminate the breeding grounds of mosquitoes and use mosquito repellents in homes to avoid a disease which results in chills and recurring fever in patients. The children of the area formed teams which inspected the surrounding areas and put few drops of oil or petrol on stagnant water pools of the area.
(i) Name the disease, causative organism and the vector of the disease which was spreading in the area.
(ii) How do the drops of petrol or oil on stagnant water prevent the spread of the disease?
(iii) What are the values shown by the students?
Answer:
(i) The disease is Malaria caused by Plasmodium and transmitted by the vector female Anopheles mosquito.

(ii) The drops of oil or petrol in the stagnant water pools kill the larvae of the mosquito as they will not be able to breathe.

(iii) The values shown by the children are: public good, helpful attitude, scientific temper and work for social good.

In this page, we are providing Improvement in Food Resources Class 9 Extra Questions and Answers Science Chapter 15 pdf download. NCERT Extra Questions for Class 9 Science Chapter 15 Improvement in Food Resources with Answers will help to score more marks in your CBSE Board Exams. https://ncertmcq.com/extra-questions-for-class-9-science/

Class 9 Science Chapter 15 Extra Questions and Answers Improvement in Food Resources

Extra Questions for Class 9 Science Chapter 15 Improvement in Food Resources with Answers Solutions

Improvement in Food Resources Class 9 Extra Questions Very Short Answer Type

Improvement In Food Resources Class 9 Extra Questions And Answers Question 1.
What is the advantage of selecting seeds of crops with wider adaptability for agriculture?
Answer:
Wider adaptability helps in stabilizing crop production under different environmental conditions.

Class 9 Science Chapter 15 Extra Questions And Answers Question 2.
Name the type of nutrient that we get from mustard seeds and linseed.
Answer:
Mustard seeds and linseed are oilseed crops that provide fats.

Improvement In Food Resources Class 9 Notes Extra Questions And Answers Question 3.
Mention any two abiotic factors that affect crop production.
Answer:
Drought, salinity, waterlogging, heat, cold and frost are the abiotic factors that affect crop production.

Improvement In Food Resources Class 9 Important Questions Question 4.
Students were asked to select one that is not a source of starch amongst the following rice, wheat, sunflower seeds, and potato tuber.
Answer:
Sunflower seeds are not a source of starch. They are a source of fats.

Improvement In Food Resources Class 9 Questions And Answers Pdf Question 5.
Improved varieties can be produced in both animals and plants. How?
Answer:
Improved varieties can be produced in both animals and plants by hybridization and genetic modification.

Ch 15 Science Class 9 Extra Questions Question 6.
Name two protein-containing Rabi crops.
Answer:
Protein containing Rabi crops are gram and peas.

Improvement In Food Resources Class 9 Questions And Answers Question 7.
Identify two crops from the following which provide us carbohydrates for energy requirement. Black gram, wheat, lentil, and rice.
Answer:
Wheat and rice provide energy.

Improvement In Food Resources Class 9 Notes Questions And Answers Question 8.
Name two plants which are used as biopesticide in organic farming.
Answer:
Turmeric and leaves of Neem plant are used as biopesticide in organic farming.

Improvement In Food Resources Question Answer Question 9.
Name the two vitamins which are added in the poultry feed.
Answer:
Vitamin A and K are the vitamins that are added in the poultry feed.

Extra Questions From Chapter Improvement In Food Resources Question 10.
Name the major nutrient which we get from fish.
Answer:
The major nutrient which we get from fish is protein.

Class 9 Improvement In Food Resources Extra Questions Question 11.
How does Catla differ from Mrigal?
Answer:
Callas are surface feeders while Mrigals are bottom feeders.

Class 9 Science Ch 15 Extra Questions Question 12.
What is mariculture?
Or
What do you mean by mariculture?
Answer:
Mariculture is a practice in which marine fishes like mullets, bhetki, and pearl spots are cultured in coastal waters on a commercial scale.

Class 9 Chapter 15 Extra Questions Question 13.
Give one example of local variety and foreign variety of bees.
Answer:
Local variety: Apis cerana Indica is commonly known as the Indian bee.
Foreign variety: Apis mellifera is the Italian variety of bee.

Important Questions Of Improvement In Food Resources Question 14.
State one factor which affects the quality of honey produced.
Answer:
The quality of honey depends upon the pasturage or the flowers available to the bees for nectar and pollen collection.

Question 15.
Give two examples of exotic breeds of cows that are selected for a long lactation period.
Answer:
Exotic or foreign breeds like Jersey and Brown Swiss are selected for long lactation periods.

Question 16.
What is meant by beekeeping?
Answer:
Beekeeping is the practice of rearing the honeybees for obtaining honey and bee wax.

Question 17.
Which species of the honeybee is commonly used for commercial honey production throughout the country?
Answer:
Apis mellifera, the Italian variety of bee is commonly used for commercial honey production throughout the country.

Improvement in Food Resources Class 9 Extra Questions Short Answer Type 1

Question 1.
Mention the names of four marine fish of high economic value.
Answer:
Fishes like mullets, bhetki, pearl spots and prawns are of high economic value.

Question 2.
Give two examples of shellfishes.
Answer:
Shellfish include prawns, mussels and oysters.

Question 3.
Name two desirable traits for variety improvement in poultry farming.
Answer:
The two desirable traits for variety improvement in poultry farming are:

• number and quality of chicks;
• dwarf broiler parent for commercial chick production.

Question 4.
Which method is commonly used for improving cattle breeds and why?
Answer:
Crossbreeding between the indigenous and exotic breeds is commonly used for improving cattle breeds. This is done as it helps to incorporate the desirable qualities like a long lactation period of exotic breeds with the disease resistance of indigenous breeds in the progeny.

Question 5.
What are ‘Sahiwal’ and ‘Jersey’ breeds?
Answer:
Sahiwal is an indigenous breed of cow whereas Jersey is the exotic breed of cow.

Question 6.
State the food requirements of dairy animals.
Answer:
The food requirements of dairy animals are of two types:

• Maintenance requirement, which is the food required to support the animal to live a healthy life.
• Milk producing a requirement, which is the type of food required during the lactation period.

Question 7.
What is mixed cropping? How does it help a farmer?
Answer:
Mixed cropping is the practice of growing two or more crops simultaneously on the same piece of land. For example, wheat and gram, or wheat and mustard, or groundnut and sunflower. It helps the farmer as it reduces the risk and gives some insurance against the failure of one of the crops.

Question 8.
State two advantages of fertilizers over manure.
Answer:
Fertilizers are more advantageous than manure as:

• Fertilizers are nutrient specific and provide the specific nutrients like N, P, K to the soil.
• They are not bulky, so are easier to transport.

Question 9.
What do you mean by vermicompost?
Answer:
The compost prepared by using earthworms to hasten the process of decomposition of plant and animal refuse is called vermicompost.

Question 10.
What are the advantages of fish farming?
Answer:
The advantages of fish farming are:

• It helps to get a large amount of desired fishes from a small area.
• It enables a variety of improvement in a better way.

Question 11.
What is a GM crop? Name anyone such crop which is grown in India.
Answer:
GM crops are the crops obtained by introducing a gene that would provide the desired characteristic to the crop plant. Bt Cotton is a genetically modified (GM) crop which has been made insect-resistant by introducing a gene from bacteria.

Question 12.
Give any two differences between macronutrients and micronutrients.
Answer:
Macronutrient:

1. Macronutrients are generally present and utilized by plant tissues in large amounts.
2. Apart from carbon, hydrogen, oxygen, the macronutrients include six elements- nitrogen, phosphorous, sulfur, potassium, calcium, and magnesium.

Micronutrient

1. The nutrients which are needed by plant tissues in small amounts are called micronutrients.
2. These include seven elements: iron, manganese, copper, zinc, molybdenum, boron, and chlorine.

Question 13.
What is a green revolution?
Answer:
An increase in crop production (especially wheat and rice) due to the use of plant breeding techniques and better farming practices, is called the green revolution.

Question 14.
What are the weeds? How do they harm crop plants?
Or
How do they prevent the growth of crops?
Answer:
The unwanted plants which grow along with the crop in the cultivated field are called weeds. Weeds compete for food, space, and light with the crop plant and reduce the growth of the crop.

Question 15.

1. What are many animals?
2. Give two examples of such animals.

Answer:

1. Milk: producing females of cattle are called many animals (dairy animals).
2. Examples of such animals are: cows, buffaloes, goats etc.

Question 16.
Mention two advantages of animal husbandry.
Answer:
Animal husbandry is advantageous to get

1. Higher milk production from cattle and higher egg production from poultry.
2. Utilization of animal wastes in a beneficial way.

Question 17.
State two characteristics of a healthy animal.
Answer:
The two characteristics of a healthy animal are:

1. A healthy animal feeds regularly.
2. Healthy animals have a normal posture.

Question 18.
Why would a cattle breeder choose to cross-breed a Jersey cow with a Red Sindhi? State two reasons.
Answer:
Jersey cows have a longer lactation period while Red Sindhi are resistant to diseases. So, the two are cross-bred to get animals with

• Long lactation period
• Resistance to diseases.

Question 19.
How are new varieties of poultry birds with desired traits produced?
Answer:
Poultry birds with desired traits are produced by crossbreeding the indigenous variety like Aseel with the exotic variety like Leghorn.

Question 20.
What desirable traits are focussed to develop by cross-breeding indigenous and exotic breeds of fowl?
Or
Mention any four desirable traits for which new varieties are produced?
Answer:
Desirable traits of poultry are:

• number and quality of chicks;
• dwarf broiler parent for commercial chick production;
• summer adaptation capacity/tolerance to high temperature;
• low maintenance requirements;
• reduction in the size of the egg-laying bird with the ability to utilize more fibrous cheaper diets formulated using agricultural by-products.

Question 21.
1. State one demerit with a composite fish culture system.
2. How can this problem be overcome?
Answer:
1. The demerit of composite fish culture system is:
(a) Many of the fishes used in the composite culture system breed only during monsoon.
(b) Lack of availability of good quality seed.
2. The problem is overcome by breeding these fish in ponds using hormonal stimulation. This ensures the supply of pure fish seed in desired quantities.

Improvement in Food Resources Class 9 Extra Questions Short Answer Type 2

Question 1.
(a) Suppose you are in charge of a grain store. How will you find out the presence of pests? Mention any two indicators.
(b) Which method is most effective for destroying insects in stored food grains, spraying or fumigation?
Answer:
(a) The indicators for the presence of pests in grain store are:
(i) Damaged or broken grains having perforations or holes.
(ii) Discoloration of grains, degraded quality of food grains.
(b) Fumigation is a better method than spraying of chemicals as the fumigants completely fill the area with gaseous particles that suffocate the pests and kill them.

Question 2.
Write a short note on marine fisheries.
Answer:
Marine fishery resources include 7500 km coastline and the deep seas beyond it. Some marine fish varieties are pomfret, mackerel, tuna, sardines, and Bombay duck. Fishes like mullets, bhetki, and pearl spots; shellfish such as prawns, mussels, and oysters as well as seaweed are of high economic value.

Question 3.
Differentiate between:
1. Inland fishery and marine fishery
2. Apiculture and aquaculture
Or
Distinguish between
1. Inland fishery and marine fishery
2. Culture fishery and capture fishery
3. Apiculture and aquaculture
Answer:
Inland Fishery:

• Inland fishery resources include canals, ponds, reservoirs, rivers and brackish water resources like estuaries and lagoons.
• Most fish production from these resources is through aquaculture.

Marine Fishery:

• Marine fishery resources include 7500 km coastline and the deep seas beyond it.
• Most fish production from these resources is through mariculture.

Apiculture:
The practice of rearing and maintenance of honeybees for obtaining honey and bee wax is called as apiculture.

Aquaculture:
The practice of breeding, rearing, and harvesting of plants and animals in all types of water environments including ponds, rivers, lakes, and the ocean.

Capture fishery:
Fish are obtained from natural resources in capture fishery.

Culture fishery:
Fish farming done in ponds or tanks is called culture fishery.

Question 4.
Differentiate between layers and broilers. What type of food should be given to broilers?
Answer:
Layers:

• The egg-laying birds which are managed for egg production are called layers.
• The layers start laying eggs at the age of 20 weeks. So, they are kept for longer periods of, around 500 days, called laying period.
• They require enough space, proper light, and hygienic conditions.
• Their feed consists of vitamins, minerals, and certain micronutrients that affect the hatchability of the eggs.

Broilers:

• The birds maintained for meat production are called broilers.
• The broilers are raised in poultry farms up to 6-7 weeks and usually weigh around 700 g to 1.5 kg.
• More stress is given to maintain the feathering, carcass quality, and low levels of mortality.
• The requirement of the broilers is protein and fat-rich food. The level of vitamin A and vitamin K is kept high in their feed.

Question 5.
What are the advantages of bee-keeping?
Answer:
The advantages of bee-keeping are:

• It helps to obtain honey and bee wax which are used in medicines and many cosmetic preparations respectively.
• It requires a very low amount of investment.
•  It is less labor-intensive.
• It helps to increase the pollination of flowers.

Question 6.
What is honey? What does the quality of honey depend upon?
Answer:
It is a sugary substance produced and stored by insects like bees in the bee-hives. It has a very high nutritional and medicinal value. The value or quality of honey depends upon the pasturage, or the flowers available to the bees for nectar and pollen collection.

Question 7.
Differentiate between the following:

1. Capture fishery and culture fishery
2. Beekeeping and Poultry farming

Answer:

1. Capture fishery: Fish are obtained from natural resources in capture fishery.
   Culture fishery: Fish farming is called culture fishery.
2. Beekeeping is the practice of rearing honeybees for obtaining honey and bee wax.
   Poultry farming is undertaken to raise domestic fowl called layers for egg production and the broilers for chicken meat.

Question 8.
Discuss various methods of weed control.
Answer:
The various methods of weed control are:
Mechanical removal, a spray of chemicals called weedicides, and preventive methods like proper seedbed preparation, timely sowing of crops, intercropping, and crop rotation.

question 9.
Discuss the role of hybridization in crop improvement.
Answer:
Hybridization is one of the methods of crop production which ensures high yield. Hybridization refers to crossing between two genetically dissimilar plants each of which possesses a particular desired character. The two varieties are cross-bred during the process to incorporate both the desirable characteristics in a single variety. This method of hybridization improves crops with respect to yield, disease resistance, pest resistance, etc.

Question 10.
What are the macro and micronutrients of plants? Name two of each kind.
Answer:
Macronutrients: The nutrients which are required in large quantities. They are six.
Example: Nitrogen, Phosphorus.
Micronutrients: The nutrients which are required in small quantities. They are seven.
Example: Iron, Copper.

Question 11.
Name any three processes in plants that are affected by deficiency in nutrients.
Answer:
Deficiency of nutrients affects the following things in plants:

• reproduction
• growth
•  susceptibility to diseases.

Question 12.
Distinguish between intercropping and mixed cropping. List any two advantages of intercropping over mixed cropping.
Answer:
Mixed cropping Growing two or more crops simultaneously on the same piece of land.
Inter-cropping: Growing two or more crops simultaneously on the same field in a definite pattern.
Intercropping is better than mixed cropping because:

• The application of pesticides to individual crop is easier and done as per the need of the crop.
• Different crops can be separately harvested and threshed.

Question 13.
What is hybridization? How is it done?
Answer:
Hybridization refers to crossing between two genetically dissimilar plants each of which possesses a particular desired character. The two varieties are cross-bred during the process to incorporate both the desirable characteristics in a single variety. This method of hybridization improves crops with respect to yield, disease resistance, pest resistance, etc.

Question 14.
How are cultivation practices and crop yield related to weather?
Answer:
1. Agriculture in India is largely dependent on the monsoon. The success of crops in most areas is dependent on timely monsoons and sufficient rainfall spread through most of the growing season. Hence, poor monsoons cause crop failure.

2. The cultivation of different varieties of crops is dependent on abiotic stresses like droughts and floods situation in an area.

Question 15.
Name any three methods of irrigation and briefly describe them.
Or
(a) Describe any two irrigation systems adopted in India to supply water to agricultural lands.
(b) Write two advantages of building check dams.
Answer:
(a) The three different types of irrigation systems are:
Wells: There are two types of wells: dug wells and tube wells. In a dug well, water is collected from water-bearing strata. Tube wells can tap water from the deeper strata. From these wells, water is lifted by pumps for irrigation.

Canals: In this system canals receive water from one or more reservoirs or from rivers. The main canal is divided into branch canals having further distributaries to irrigate fields.

River Lift Systems: In this system, water is directly drawn from the rivers for supplementing irrigation in areas close to rivers.

The advantage of check dams are-

• Leads to an increase in groundwater levels.
• The check-dams stop the rainwater from flowing away and reduce soil erosion.

Question 16.
What factors may be responsible for losses of grains during storage? Give one example of both. Give one method/preventive measure to control such losses.
Or
What preventive and control measures should be taken before the storage of grains?
Answer:
Factors responsible for losses of grains during storage are:

• Biotic: insects, rodents, fungi, mites, and bacteria
• Abiotic: inappropriate moisture and temperatures in the place of storage.

Ways to reduce loss during storage of grains:

1. Proper treatment and systematic management of warehouses.
2. They include strict cleaning of the produce before storage.
3. Proper drying of the product first in sunlight and then in shade.
4. Fumigation using chemicals that can kill pests.

Question 17.
List six facilities that must be provided to cattle to ensure their good health and production of clean milk.
Answer:
Six facilities that must be provided to cattle to ensure their good health and production of clean milk are:

• The cattle should be housed in well-ventilated sheds,
• The floor of the cattle shed needs to be sloping so as to stay dry and to facilitate cleaning.
• The feeding of cattle should be carried out in a scientific manner. The feed should have:

(a) Roughage, which is largely fiber and
(b) Concentrates, which are low in fiber and have high levels of proteins and other nutrients.

• Leads to an increase in groundwater levels.
• The check-dams stop the rainwater from flowing away and reduce soil erosion.

Question 18.
What is the lactation period? Name two breeds of cattle that are selected for their lactation period. Why are they crossed with local breeds?
Answer:
The period of milk production after the birth of a calf is called the lactation period. Milk production can be increased by increasing the lactation period. Exotic or foreign breeds like Jersey and Brown Swiss are selected for long lactation periods. They (exotic breeds) are crossed with local breeds to get animals with the desired qualities of both the animals.

Question 19.
Which variety of honeybee is advantageous – Apis cerana indica or Apis mellifera and why?
Answer:
Apis mellifera, the Italian variety of bee is better than Apis cerana indica. It has the following advantages:

• They have high honey collection capacity.
• They sting somewhat less.
• They stay in a given beehive for long periods and breed very well.

Question 20.
Match the column A with column B

Answer:
(a) (ii) Surface feeders
(b) (iii) Middle-zone feeders
(c) (i) Bottom feeders
(d) (iv) Culture fishery

Question 21.
Fill in the blanks
(a) Pigeon pea is a good source of ………..
(b) Berseem is an important ………… crop.
(c) The crops which are grown in the rainy season are called ………… crops.
(d) ………… are rich in vitamins.
(e) ………… crop grows in the winter season.
Answer:
(a) protein
(b) fodder
(c) Kharif
(d) Vegetables
(e) Rabi

Question 22.
What is a GM crop? Name anyone such crop which is grown in India.
Answer:
GM crops are the crops obtained by introducing a gene that would provide the desired characteristic to the crop plant. Bt Cotton is a genetically modified (GM) crop which has been made insect-resistant by introducing a gene from bacteria.

Question 23.
List out some useful traits in the improved crop.
Answer:
Some useful traits of improved crops are:
(a) higher yield
(b) improved nutritional quality
(c) resistance to biotic and abiotic stresses
(d) change in maturity duration
(e) wide range of adaptability
(f) desired agronomic characteristics.

Question 24.
Why is organic matter important for crop production?
Answer:
Organic matter is important for crops production because:
(a) it helps in improving soil structure.
(b) it helps in increasing water holding capacity of sandy soil.
(c) It helps in drainage and in avoiding water logging in clayey soils.

Question 25.
Why is excess use of fertilizers detrimental for the environment?
Answer:
Excess use of fertilizers is detrimental for the environment as their residual and unused amounts become pollutants for air, water, and soil. The fertilizers get washed away in the nearby water bodies and cause excessive growth of algae and aquatic plants which can adversely affect the aquatic life and drain the oxygen from water bodies.

Question 26.
Give one word for the following:
(a) Farming without the use of chemicals as fertilizers, herbicides and pesticides is known as ……….
(b) Growing of wheat and groundnut on the same field is called as ……….
(c) Planting soybean and maize in alternate rows in the same field is called as ……….
(d) Growing different crops on a piece of land in pre-planned succession is known as ……….
(e) Xanthium and Parthenium are commonly known as ……….
(f) The causal organism of any disease is called as ……….
Answer:
(a) organic farming
(b) mixed cropping
(c) intercropping
(d) crop-rotation
(e) weeds
(f) pathogen

Question 27.
Match the following A and B

Answer:
(a) → (iii) Drought animals
(b) → (v) Aseel
(c) → (iv) The local breed of cattle
(d) → (i) Milk producing female
(e) → (ii) Broiler

Question 28.
If there is low rainfall in a village throughout the year, what measures will you suggest to the farmers for better cropping?
Answer:
If there is low rainfall in a village throughout the year, then the farmers will be suggested to:
(a) Cultivate crops varieties that are drought resistant and early maturing.
(b) Increase the humus content of the soil in order to increase its water holding capacity.

Question 29.
Group the following and tabulate them as energy-yielding, protein yielding, oil yielding, and fodder crop. Wheat, rice, berseem, maize, gram, oat, pigeon gram, sudangrass, lentil, soybean, groundnut, castor, and mustard.
Answer:

1. Energy yielding: wheat, rice, maize
2. Protein yielding: gram, pigeon gram, lentil, soybean
3. Oil yielding: groundnut, castor, mustard, soybean
4. Fodder crops: berseem, oat, sudangrass

Question 30.
Define the term hybridization and photoperiod.
Answer:
Hybridization is one of the methods of crop production which involves crossing between two genetically dissimilar plants each of which possesses a particular desired character. The photoperiod is the duration of sunlight available to the plant. It affects the growth, flowering, and maturation of crops.

Question 31.
Fill in the blanks
(a) Photoperiod affects the ………..
(b) Kharif crops are cultivated from ……….. to ………..
(c) Rabi crops are cultivated from ……….. to ………..
(d) Paddy, maize, green gram and black gram are ……….. crops.
(e) Wheat, gram, pea, mustard are ……….. crops.
Answer:
(a) Flowering of plants
(b) June to October
(c) November to April
(d) Khalil
(e) Rabi

Question 32.
Cultivation practices and crop yield are related to environmental conditions. Explain.
Answer:
Different crops and cultivation practices require different climatic conditions, temperature, photoperiod for their growth and completion of life cycle. Depending upon these conditions some crops called Kharif crops are grown in rainy season while others called as the Rabi crops are grown during winter season.

Question 33.
Fill in the blanks
(a) A total of ……….. nutrients are essential to plants.
(b) ……….. and ……….. are supplied by air to p1ants.
(c) ……….. is supplied by water to plants.
(d) Soil supply ……….. nutrients to plants.
(e) ……….. nutrients are required in large quantity and called.
(f) ……….. nutrients are needed in small quantity for plants and are called.
Answer:
(a) 16 (Sixteen)
(b) Carbon, oxygen
(c) Hydrogen
(d) 13 (Thirteen)
(e) Six, macro
(f) Seven, micro

Question 34.
Differentiate between compost and vermicompost.
Answer:
1. Compost: Compost is prepared by decomposition of the farm waste materials like livestock excreta (cow dung, etc.), vegetable waste, animal refuse, domestic waste, sewage waste, straw, eradicated weeds, etc., in pits.
2. Vermicompost: The compost is called as vermicompost if it is prepared by using earthworms to hasten the process of decomposition of plant and animal refuse.

Question 35.
Arrange these statements in the correct sequence of preparation of green manure.
(a) Green plants are decomposed in soil.
(b) Green plants are cultivated for preparing manure or crop plant parts are used.
(c) Plants are plowed and mixed into the soil.
(d) After decomposition, it becomes green manure.
Answer:
(b)→(c)→(a)→(d)

Question 36.
An Italian bee variety A. mellifera has been introduced in India for honey production. Write about its merits over other varieties.
Answer:
The Italian bee variety A. mellifera has the following advantages:

• They have high honey collection capacity.
• They sting somewhat less.
• They stay in a given beehive for long periods and breed very well.

Question 37.
In agricultural practices, higher input gives a higher yield. Discuss how.
Answer:
The financial conditions of the farmers allow them to take up different farming practices and technologies. The cropping system and production practices of the farmer are decided by the farmer’s purchasing capacity for input. A higher money input helps to raise the yield. So, we can say that in agricultural practices, higher input gives a higher yield.

Improvement in Food Resources Class 9 Extra Questions Long Answer Type

Question 1.
Mention the modern initiatives undertaken in India to supply water to the fields.
Answer:
Indian agriculture is mainly dependent on the monsoons. The irregular or scarcity of rainfall often results in crop failure. To overcome the problem, different types of irrigation systems are in practice in India for the supply of water in agricultural fields. Wells, canals, river lift systems, tanks, etc. are used for irrigation. Some new initiatives like rainwater harvesting and watershed management are being used.

For this small check-dams are constructed to stop the rainwater from flowing and lead to an increase in groundwater levels. The different types of irrigation systems are:

1. Wells: There are two types of wells – dug wells and tube wells. In a dug well, water is collected from water-bearing strata. Tube wells can tap water from the deeper strata. From these wells, water is lifted by pumps for irrigation.

2. Canals: In this system canals receive water from one or more reservoirs or from rivers. The main canal is divided into branch canals having further distributed to irrigate fields.

3. River Lift Systems: In this system, water is directly drawn from the rivers for supplementing irrigation in areas close to rivers.

4. Tanks: These are small storage reservoirs, which intercept and store the run-off of smaller catchment areas.

Question 2.
What do you understand by composite fish culture? Describe in detail with advantages and disadvantages. What are the advantages of composite fish culture?
Answer:
A combination of five or six fish species is used in a single fish pond in the composite fish culture system. The selected species do not compete for food among them as they have different types of food habits.

The types of fishes used are:
Callas are surface feeders, Rohus feed in the middle-zone of the pond, Mrigals, and Common Carps are bottom feeders, and Grass Carps feed on the weeds. As a result, the food available in all the parts of the pond is used.

Advantages of Composite fish culture:

• The species of fishes in the pond utilize all the food available in the pond.
• The species do not compete with each other for food as they have different food habits.
• The yield of fish is increased by such a culture system.

The disadvantage of Composite fish culture:
A major problem in fish farming is the lack of availability of good quality fish seeds.

Question 3.
How do plants get their nutrients?
Or
List the nutrients supplied by air, water, and soil.
Answer:

Question 4.
Define manures. What are its different kinds? State two limitations of manures.
Answer:
Manure is prepared by the decomposition of animal excreta and plant waste and contains a lot of organic matter which helps in enriching the soil with nutrients and increasing soil fertility. Manure is classified on the basis of kind of biological material used as:

1. Compost: Compost is prepared by decomposition of the farm waste materials like livestock excreta (cow dung etc.), vegetable waste, animal refuse, domestic waste, sewage waste, straw, eradicated weeds, etc., in pits.

2. Vermicompost: The compost is called vermicompost if it is prepared by using earthworms to hasten the proœss of decomposition of plant and animal refuse.

3. Green manure: Green plants like sun hemp or guar are grown and then mulched by plowing them into the soil prior to the sowing of the crop seeds to enrich the soil in nitrogen and phosphorus.

The limitations of manure are:

1. They do not supply a specific nutrient.
2. They are not readily soluble in water so their absorption by plants is slower.
3. They are bulky in nature and difficult to be transported.
4. Only small amounts of nutrients are supplied by the manure.

Question 5.
Differentiate between manures and fertilizers.
Or
Compare manure and fertilizer in three points.
Manure:

1. Manure is prepared by the decomposition of animal excreta and plant waste.
2. They are bulky and difficult to be transported.
3. They are not nutrient-specific in nature.
4. They are not readily soluble in water and thus absorbed slowly by plants.
5. Manure contains a lot of organic matter.
6. They are environment friendly in nature.
7. Difficult to store.

Fertilizer:

1. Fertilizers are commercially produced plant nutrients.
2. They are not bulky, so easier to transport.
3. They are nutrient-specific in nature.
4. They are easily absorbed by the plants as they are soluble in water.
5. They do not contain organic matter.
6. The comparatively less environmentally friendly.
7. Easier to store.

Question 6.
Mention the management practices that are common between dairy and poultry farming.
Answer:
Management practices which are common between dairy and poultry fanning are:

• Should be housed in the well-ventilated shelter.
• Proper cleanliness should be maintained.
• Regular visits by a doctor and timely vaccination.
• Balanced food should be provided with additives.
• Regular inspections, with proper record keeping.

Question 7.
What are the differences between broilers and layers with respect to their purpose of breeding and daily requirement? What necessary steps have to be taken to prevent the occurrence of infectious diseases in poultry farms?
Answer:
The meat-producing birds are called broilers and the egg-laying birds are called layers. The housing, nutritional and environmental requirements of the broilers are different from the layers. The broilers are raised in poultry farms up to 6-7 weeks and usually weigh around 700 g to 1.5 kg.

The requirement of the broilers is protein and fat-rich food. The level of vitamin A and vitamin K is kept high in their feed. Care is taken to avoid mortality and to maintain the feathering and carcass quality. The layers start laying eggs at the age of 20 weeks. So, they are kept for longer periods of around 500 days, called laying period. They require enough space, proper light, and hygienic conditions.

heir feed consists of vitamins, minerals, and certain micronutrients that affect the hatchability of the eggs. Necessary steps for prevention of infectious diseases are:
1. Proper cleaning, sanitation, and spraying of disinfectants at regular intervals.
2. Appropriate vaccination to prevent the occurrence of infectious diseases.

Question 8.
Discuss the role of hybridization in crop improvement.
Answer:
Hybridization is one of the methods of crop production which ensures high yield. Hybridization refers to crossing between two genetically dissimilar plants each of which possesses a particular desired character. The two varieties are cross-bred during the process to incorporate both the desirable characteristics in a single variety. This method of hybridization improves crops with respect to yield, disease resistance, pest resistance, etc.

Question 9.
Define
1. Vermicompost
2. Green manure
3. Biofertilizer
Answer:
1. Vermicompost: The compost prepared by using earthworms to hasten the process of decomposition of plant and animal refuse.
2. Green manure: The manure which is prepared by decomposing green plants in field itself is called green manure. For example: sun hemp is grown in fields, mulched by plowing and allowed to
decompose infield for the preparation of green manure. It helps in enriching the soil in nitrogen and phosphorus.
3. Biofertiliser: Living organisms which are used as fertilizer to supply the nutrients to plants, are called as biofertilizers. For example, blue-green algae which fix nitrogen in soil, rice fields, are called biofertilizers.

Question 10.
Discuss various methods of weed control.
Answer:
The various methods of weed control are mechanical removal, a spray of chemicals called weedicides and preventive methods like proper seedbed preparation, timely sowing of crops, intercropping and crop rotation.

Question 11.
Differentiate between the following

1. Capture fishery and Culture fishery
2. Mixed cropping and Inter-cropping
3. Beekeeping and Poultry farming

Answer:

1. Capture fishery: Fish are obtained from natural resources in capture fishery. Culture fishery: Fish farming is called culture fishery.
2. Mixed cropping: Growing two or more crops simultaneously on the same piece of land. Inter-cropping: Growing two or more crops simultaneously on the same field in a definite pattern.
3. Beekeeping is the practice to rear honeybee for obtaining honey. Poultry farming is undertaken to raise domestic fowl called layers for egg production and the broilers for chicken meat.

Question 12.
Give the merits and demerits of fish culture.
Answer:
The merits and demerits of fish culture are:
Merits:

• It helps to get a large amount of desired fishes from a small area.
• It enables a variety of improvements in a better way.

Demerits:

• It is a threat to bio-diversity as only selected varieties are cultured on a large scale.
• It involves the culture of only economically important and valued fishes.

Question 13.
What do you understand by composite fish culture?
Answer:
A combination of five or six fish species is used in a single fish pond in the composite fish culture system. The selected species do not compete for food among them as they have different types of food habits.

The types of fishes used are:
Callas are surface feeders, Rohus feed in the middle-zone of the pond, Mrigals and Common Carps are bottom feeders, and Grass Carps feed on the weeds. As a result, the food available in all the parts of the pond is used.

Question 14.
Why should beekeeping be done in good pasturage?
Answer:
Beekeeping should be done in good pasturage as it:

• Helps in increasing the honey yield.
• Helps in increasing pollination efficiency.
• Provides better quality and quantity of nectar for the honey bees.

Question 15.
Write the modes by which insects affect the crop yield.
Answer:
The modes by which insects affect the crop yield are

• they cut the root, stem and leaf,
• they suck the cell sap from various parts of the plant, and
• they bore into stem and fruits.

Question 16.
Discuss why pesticides are used in very accurate concentration and in a very appropriate manner.
Answer:
Pesticides should be used in very accurate concentration and in a very appropriate manner because it
may have the following adverse effects:
(a) They harm the soil and causes loss of fertility
(b) They act as a check on the replenishment of organic matter
(c) They kill the microorganism of soil and destroy the soil structure
(d) They cause air, water and soil pollution.

Question 17.
Name two types of animal feed and write their functions.
Answer:
The two types of animal feed are:

• Roughage, which is largely fiber.
• Concentrates, which are low in fiber and have high levels of proteins and other nutrients.

Question 18.
What would happen if poultry birds are larger in size and have no summer adaptation capacity? In order to get small sized poultry birds, having summer adaptability, what method will be employed?
Answer:
Maintenance of temperature is needed for better egg production by poultry birds. The egg production is declined due to larger size (increase in surface area of the body) and no adaptability of summer in poultry birds. So, cross-breeding of poultry birds is done to obtain smaller size and higher summer adaptability in them. Small size is ais? needed for better housing and lower feed requirements.

Question 19.
Suggest some preventive measures for the diseases of poultry birds.
Answer:
Some preventive measures of poultry bird diseases are
(a) cleaning of poultry farms
(b) proper sanitation of poultry farms
(c) spraying of disinfectants at regular intervals
(d) appropriate vaccination of birds.

Question 20.
The figure shows the two crop fields [Plots A and BI have been treated by manures and chemical fertilizers respectively, keeping other environmental factors same. Observe the graph and answer the following questions.

1. Why does plot B show a sudden increase and then a gradual decrease in yield?
2. Why is the highest peak in plot A graph slightly delayed?
3. What is the reason for the different patterns of the two graphs?

Answer:
1. With the addition of chemical fertilizer, there is a sudden increase in yield due to the release of nutrients Nitrogen, Phosphorus, Potassium (NPK), etc. in high quantity. The gradual decline in the graph may be due to continuous use and a high quantity of chemicals that kill microbes useful for replenishing the organic matter in soil. This decreases soil fertility.

2. Manures supply small quantities of nutrients to the soil slowly as it contains large amounts of organic matter. It enriches soil with nutrients thereby increasing soil fertility continuously.

3. The difference in the two graphs indicates that use of manure is beneficial for a long duration in cropping as the yield tends to remain high when the number of manure increases.

4. In the case of Plot B the chemical fertilizers may cause various problems when used continuously for long time. Loss of microbial activity reduces the decomposition of organic matter and as a result, the soil fertility is lost that affects the yield.

Question 21.
Complete the crossword puzzle

Across:
1. Oil yielding plant (9)
3. Crop grown in winter season (4)
5. Fixed by Rhizobium (8)
9. Common honey bee (4)

Down:
2. Animal feed (6)
4. A micronutrient (5)
6. Unwanted plant in crop fields (4)
7. An exotic breed of chicken(7)
8. Bottom feeders in fish pond(7)
10. A marine fish (4)
Answer:

Improvement in Food Resources Class 9 Extra Questions HOTS

Question 1.
Irrigation systems are in practice in India for the supply of water in agricultural fields. Why?
Answer:
Most agriculture in India is rain-fed and the success of crops in most areas is dependent on timely monsoons and sufficient rainfall. Poor monsoons can cause crop failure. Hence, in order to ensure that the crops get water at the right stages during their growing season, irrigation systems are in practice in India for the supply of water to agricultural fields.

Question 2.
Nitrogenous fertilizers are usually not required by the leguminous crops. Why?
Answer:
The leguminous crops have root nodules that harbor nitrogen-fixing bacteria like Rhizobium in them. These bacteria convert the atmospheric nitrogen to nitrates for their utilization by plants. So, nitrogenous fertilizers are usually not required by the leguminous crops.

Question 3.
Why are crops like guar grown by some farmers before sowing the seeds of a crop?
Answer:
The crops like guar are grown by farmers before sowing the seeds of a crop as the guar crop is mulched by plowing. It turns into green manure which helps in enriching the soil in nitrogen and phosphorus.

Question 4.
Why is the enhancement of food production becoming a major necessity? Which group of activities are required for improving the crop yields?
Answer:
Enhancement of food production has become a major necessity because:
1. The population of the world is increasing at a faster rate, so it is needed to fulfill the food requirements of the population.
2. The land available for cultivation is limited, so the only option available is to increase crop production.

Major groups of activities for improving crop yields:

• Crop variety improvement
• Crop production improvement
• Crop protection management

Question 5.
List some dairy farming practices needed to increase the milk yield potential of cattle.
Answer:
The dairy farming practices needed to increase the milk yield potential of cattle are:

1. The cattle should be housed well and have adequate water.
2. The cattle should be kept disease-free.
3. The feeding of cattle should be carried out in a scientific manner with special emphasis on the quality and quantity of fodder.
4. Stringent cleanliness and hygiene should be maintained.
5. Regular inspections of cattle should be done with proper record keeping.
6. Regular visits by a veterinary doctor should be ensured.

Improvement in Food Resources Class 9 Extra Questions Value Based (VBQs)

Question 1.
Aniket took admission in a dairy research institute and took an active interest in his studies. During the course, he got an opportunity to visit a village. He met the farmers there and advised them about dairy farm practices which can help to increase the milk yield of their cattle. The farmers were able to get an increased yield due to his advice.

1. Name two species of cattle in India.
2. List two measures that would have been suggested by Aniket to increase milk yield.
3. What values are shown by Aniket?

Answer:
1. Indian cattle belong to two different species, Bos indicus, cows, and Bos bubble.s, buffaloes.
2. The measures which would have been suggested by Aniket to increase milk yield are:
(a) The cattle should be housed well and have adequate water.
(b) The cattle should be kept disease-free.
(c) The feeding of cattle should be carried out in a scientific manner with special emphasis on the quality and quantity of fodder.
3. The values shown by Aniket are a concern for others, caring nature, scientific approach, and knowledge.

Question 2.
Sonam got admission in a reputed institute engaged in agricultural research. After the completion of course she decided to go and serve the people of her village. Her village was suffering from a reduction in infertility of the soil and high salinity in soil. She called a meeting of farmers and told them that the use of fertilizers has increased the salinity of the soil. She suggested to them the use of manures and cropping patterns to get better yields.

1. What are the different types of manures which can be used?
2. Name the different cropping patterns which she would have suggested.
3. What values are shown by Sonam?

Answer:

1. The types of manures which can be used are: Compost, vermicompost, and green manure.
2. The different cropping patterns can be inter-cropping, mixed cropping, and crop rotation.
3. The values shown by Sonam are sincerity towards work, scientific aptitude, and concern for others.

In this page, we are providing Motion Class 9 Extra Questions and Answers Science Chapter 8 pdf download. NCERT Extra Questions for Class 9 Science Chapter 8 Motion with Answers will help to score more marks in your CBSE Board Exams. https://ncertmcq.com/extra-questions-for-class-9-science/

Class 9 Science Chapter 8 Extra Questions and Answers Motion

Extra Questions for Class 9 Science Chapter 8 Motion with Answers Solutions

Motion Class 9 Extra Questions Very Short Answer Type

Motion Class 9 Extra Questions Question 1.
Define the following terms:
(a) Distance
(b) Displacement
(c) Speed
(d) Velocity
(e) Acceleration
(f) Uniform motion
(g) Uniform circular motion
(h) Scalar quantity
(i) Vector quantity
Answer:
(a) Distance: The total path length traveled by a body in a given interval of time is called distance.
(b) Displacement: The shortest distance measured from the initial to the final position of an object is known as displacement.
(c) Speed: The speed of a body is defined as the distance traveled per unit time.
(d) Velocity: Velocity is defined as displacement per unit time.
(e) Acceleration: The rate of change of velocity with respect to time.
(f) Uniform motion: A body moving in a straight line has a uniform motion if it travels the equal distance in equal intervals of tune.
(g) Non-uniform motion: A body has a non-uniform motion if it travels unequal distances in equal intervals of time.
(h) Scalar quantity: A physical quantity which is described completely by its magnitude only, is called a scalar quantity.
(i) Vector quantity: A physical quantity that has magnitude as well as direction and obeys the vector addition is called a vector quantity.

Motion Chapter Class 9 Extra Questions And Answers Question 2.
Draw position-time graph of a body that started from a position other than origin and moving with uniform speed.
Answer:

Class 9 Motion Extra Questions Question 3.
Give one example where the displacement is zero but the distance traveled is not zero.
Answer:
When a body completes one rotation in a circular path its initial and final positions are the same and hence its displacement is zero.

Class 9 Motion Numericals Extra Questions Question 4.
The area under the velocity-time curve represents which physical quantity?
Answer:
Distance and displacement.

Motion Extra Questions Class 9 Question 5.
Under what conditions, distance, and magnitude of the displacement are equal?
Answer:
Distance and displacement are equal fan object move along a straight line in one direction.

Class 9 Science Chapter 8 Extra Questions And Answers Question 6.
What is the numerical ratio of average velocity to the average speed of an object when it is moving in a straight path?
Answer:
In this case, both are equal, so the ratio is 1.

Motion Chapter Class 9 Extra Questions And Answers Numericals Question 7.
What does the speedometer of an automobile measure?
Answer:
The speedometer of a vehicle measures its instantaneous speed.

Extra Questions Of Motion Class 9 Question 8.
Classify the following quantities on the basis of scalar quantities and vector quantities.
(a) Distance
(b) Displacement
(c) Speed
(d) Velocity
(e) Acceleration
Answer:
(a) Distance: Scalar quantity
(b) Displacement: vector quantity
(c) Speed: Scalar quantity
(d) Velocity: Vector quantity
(e) Acceleration: Vector quantity

Extra Questions On Motion Class 9 Question 9.
An object starts with initial velocity y and attains a final velocity y. The velocity is changing at a uniform rate. What is the formula for calculating average speed in this situation?
Answer:

Extra Questions For Class 9 Physics Motion Question 10.
What will you say about the motion of an object if its distance-time graph is a straight line with having a constant angle with a time axis?
Answer:
The motion of the body is uniform motion (constant speed).

Class 9 Science Motion Extra Questions Question 11.
What will you say about the motion of a body if its velocity-time graph is a straight line parallel to the time axis?
Answer:
The velocity of the body is constant.

Class 9 Science Ch 8 Extra Questions Question 12.
A physical quantity measured is -20 ms^-1 It is speed or velocity?
Answer:
It is velocity because velocity can be positive or negative while speed cannot be negative.

Class 9 Physics Motion Extra Questions Question 13.
A motorcycle drives from A to B with a uniform speed of 30 kmh¹ and returns hack with a speed of 20 kmh¹. Find its average speed.
Answer:
Let distance AB = x km.
Time taken from going A to B; t₁ = \(\frac {x}{30}\) h
Time taken from goingBto A; t₂ = \(\frac {x}{20}\) h
Total time taken,t = t₁ + t₂ = \(\frac {x}{30}\) + \(\frac {x}{20}\) = \(\frac {x}{50}\) h
total distance = x + x = 2x km

∴ Average speed = 24 km/h

Ch 8 Science Class 9 Extra Questions Question 14.
A man swims in a pool of width 300 m. He covers 600 m in 10 minutes by swimming from on end to the other, and back along the same path. Find the average speed and average velocity of the man for the entire journey.
Answer:
Total distance covered by the man in 10 minutes = OA + AB = 600 m
Displacement of man in 10 minutes = 0 m

Average speed = 1 m/s

Average velocity = 0 m/s

Extra Questions For Class 9 Science Chapter Motion With Answers Question 15.
What is the acceleration of a body moving with uniform velocity along a straight line?
Answer:
Acceleration of the body is zero as the velocity is constant.

Question 16.
Give an example of a uniform circular motion.
Answer:
An athlete running on a circular track with constant speed.

Question 17.
Convert speed 54 km in meter per second.
Answer:
Speed = 54 km/h =54 x \(\frac{1000 m}{3600}\) = 15 m/s

Question 18.
What ¡s the nature of the distance-time graph for accelerated motion?
Answer:

Motion Class 9 Extra Questions Short Answer Type 1

Question 1.
Distinguish between speed and velocity.
Answer:
Speed:

• Speed is the ratio of distance and time.
• Speed is always positive
• Speed is a scalar quantity.

Velocity:

• Velocity is the ratio of displacement and time.
• Velocity may be negative or positive.
• Velocity is a vector quantity.

Question 2.
Distinguish between distance and displacement.
Answer:
Distance

• It is the actual length of the path covered by a moving body.
• It is always positive or zero.
• It is a scalar quantity.

Displacement:

• It is the shortest distance measured between the initial and final positions.
• It may be positive, negative, or zero.
• it is a vector quantity.

Question 3.
Write down the SI unit of the following quantities:
(a) Displacement
(b) Speed
(c) Velocity
(d) Acceleration
Answer:
(a) m
(b) m/s
(c) m/s
(d) m/s²

Question 4.
Distinguish between uniform motion and non-uniform motion.
Answer:
1. Uniform motion:
A body moving in a straight line has a uniform motion if it travels the equal distance in equal intervals of time

2. Non.uniform motion:
A body has a non-uniform motion if it travels the unequal distance in equal intervals of time

Question 5.
Distinguish speed at any instant and average speed.
Answer:
1. Instantaneous speed:
The speed at any particular instant is known as instantaneous speed.

2. Average speed:
Average speed is the ratio of total distance traveled by a body and time taken to travel that distance.

Question 6.
Draw a velocity versus time graph of a stone thrown vertically upwards and then coming downwards after attaining the maximum height.
Answer:
velocity-time graph

Question 7.
What is uniform circular motion? How is uniform circular motion regarded as an acceleration motion? Explain.
Answer:
When an object is moving in a circular path with a constant speed, the motion of an object is said to be uniform circular motion. When a body has a uniform circular motion, its velocity changes due to the continuous change in the direction of its motion. Hence, the motion of the body is accelerated motion.

Motion Class 9 Extra Questions Numericals

Question 8.
A person travels a distance of 4.0 m towards the east, then turns left and travels 3.0 m towards the north.
1. What is the total distance traveled by the person? North
2. What is his displacement?
Answer:
1. Total distance = OA + AB
= 4m + 3m
Total distance = 7m

2. Total displacement = OB = \(\sqrt{(O A)^{2}+(A B)^{2}}\)
=\(\sqrt{(4)^{2}+(3)^{2}}\) = \(\sqrt{25}\) = 5
Displacement = 5 m

Question 9.
A person travels on a semi-circular track of radius 50 m during a morning walk. If he starts from one end of the track and reaches the other end, calculates the distance traveled and displacement of the person.
Answer:
Let the person start moving from A and reach B via O.
The distance travelled by the person
= Length of track = πr
= \(\frac{22}{7}\) x 50 m = 157.14m
Distance = 157.14 m
The displacement is equal to the diameter of the semi-circular track joining A to B via O.
= 2r = 2 x 50 m = 100m
∴ Displacement = 100 m

Question 10.
Dinesh takes 20 minutes to cover a distance of 5 km on a bicycle. Calculate his average speed in
1. m/s
2. km/h
Answer:
1. Average speed in metre/second
Distance travelled by Dmesh = 5 km = 5 x 1000 m = 5000 m
time taken (t) = 20 min = 20 x 60 seconds = 1200 seconds

2. Average speed in kilometre/hour
Average speed = \(\frac{5 \mathrm{km}}{\frac{20}{60} \mathrm{h}}\) = 15 km/h
∴  Average speed = 15 km/h

Question 11.
A train starting from a railway station and moving with uniform acceleration attains a speed of 20 m/s in 10 seconds. Find its acceleration.
Answer:
Given,
initial velocity, u = 0 m/s
Final velocity, υ = 20 m/s
time taken, t = 10 s
Acceleration, a = \(\frac{v-u}{t}=\frac{20-0}{10}\)
∴ a = 2 m/s²

Question 12.
A car moving with a speed of 72 km/h is brought to rest in 10 seconds by applying brakes. Find the magnitude of average retardation due to brakes and distance traveled by car after applying the brakes.
Answer:
Given, initial velocity = 72 km/h = 72 x \(\frac{5}{18}\) = 20 m/s
Final velocity = 0 m/s
Time taken = 10s.

1. Retardation
Acceleration, a = \(\frac{υ – u}{t}\)
a = \(\frac{0 – 20}{10}\) = -2m/s²
∴ Retardation = 2 m/s²

2. Distance travelled using equation, υ² – u² = 2as
(0)² – (20)² = 2 (-2)s
∴ s = 100 m

Question 13.
The velocity of a particle moving along a straight line in a certain time interval is shown below. What is the distance traveled during acceleration?

Answer:
Here particle accelerates for 2 seconds.
Distance traveled during acceleration = area under υ – t graph for 2 sec.
\(\frac{1}{2}\) x Base x Height = \(\frac{1}{2}\) x 2 x 20 = 20m

Question 14.
A girl walks along a straight path to drop a letter in the letterbox and comes back to her initial position. Her displacement—
The time graph is shown in the figure. Plot a velocity-time graph for the same.
Answer:
Velocity-time graph

Question 15.
Obtain a relation for the distance traveled by an object moving with uniform acceleration in the time interval between the 4th and 5th seconds.
Answer:
Using equation, s = ut + \(\frac{1}{2}\) at²
Distance travelled in 5 s; s₁ = u x 5 + \(\frac{1}{2}\) a(5)²
s₁ = 5u + \(\frac{25a}{2}\)

Distance travelled in 4 s; s₂ = u x 4 + \(\frac{1}{2}\) a(4)²
s₂ = 4u x 8a
Distance travelled in the interval between 4^th and 5^th sec.
= s₁ – s₁ = (5u + \(\frac{25a}{2}\)) – (4u + 8a)
∴ Distance travelled = u + \(\frac{9a}{2}\)

Motion Class 9 Extra Questions Short Answer Type 2

Question 1.
Draw a position-time graph of for
(a) rest
(b) uniform motion
(c) Non-uniform motion
Answer:
(a) Position – time graph for rest

(b) Position – time graph for uniform motion

(c) Position – time graph for non-uniform motion

Question 2.
A draw velocity-time graph for
(a) Uniform motion
(b) Uniform acceleration
(c) Uniform retardation
Answer:
(a) Velocity – time graph for uniform motion (Const. speed)

(b) Velocity – time graph for uniform acceleration (Const. acceleration)

(c) Velocity – time graph for uniform retardation

Question 3.
Explain the difference between the two graphs.

Answer:
(a) In the first graph, the body is starting its motion from origin but in the second graph, the body is starting its motion from any other point.
(b) In the first graph, the body has zero initial velocity but in the second graph the body has non-zero initial velocity.

Question 4.
Two stones are thrown vertically upwards simultaneously with their initial velocities u1 and u2 respectively. Prove that the heights reached by them would be in the ratio of \(\frac{1}{2}\)
(Assume upward acceleration is – g and downward acceleration to be +g).
Answer:
The maximum height reached by the stone can be calculated by the formula
υ² – u² = 2as
Here, υ = 0 and a= – g
Applying this equation for the first ball

Motion Class 9 Extra Questions Numericals

Question 5.
Study the velocity-time graph of a traveling metro train as shown in the figure. What is the acceleration of the train
(a) during the first two seconds?
(b) between the second and tenth seconds?
(c) during the last two seconds?

Answer:
(a) Acceleration, a = \(\frac {v – u}{t}\)
Here, u = 0, u = 20m/s and t = 2s
a = \(\frac {20 – 0}{2}\) = 10 m/s²

(b) Here, u = 20m/s, υ = 20m/s and t = 8s
a = \(\frac {20 – 0}{2}\) = 0 m/s²

(c) Here, u = 20 m/s, u = 0 m/s and t = 2s
a = 0 – 20 = – 10 m/s²

Question 6.
An electron moving with a velocity of 5 x 10 ms¹ enters into a uniform electric field and acquires a uniform acceleration of 10 ms² in the direction of its initial motion.
1. Calculate the time in which the electron would acquire a velocity double its initial velocity.
2. How much distance would the electron cover in this time?
Answer:
Given, u =5 x 10 m/s²
a = 10⁴ m/s²

1. From υ = u + at
take υ = 2u
2u = u + at
u = at
5 x 10⁴ = 10⁴ x t
∴ t = 5s

2. From s = ut + \(\frac{1}{2}\) at²
s = 5 x 10⁴ x 5 + \(\frac{1}{2}\) x 10⁴ x (5)²
∴ s = 37.5 x 10⁴ m

Question 7.
The motion of a train is described by the velocity-time graph as shown in the figure given below.

Find distance travelled by car between
1. 0 to 20 s
2. 20 s to 50 s
Answer:
Distance travelled = Area of velocity – time curve
1. For (0 to 20 s)
Distance = Area of ΔOAC = \(\frac{1}{2}\) x OC x AC = \(\frac{1}{2}\) x 20 x 10 = 100 m

2. For (20 s to 50 s)
Distance = Area of rectangle ABDC + Area of ΔBED
Distance = AC x CD + \(\frac{1}{2}\) DE x DB = 10 x (40 – 20) + \(\frac{1}{2}\) x 10 x 5 = 225m

Motion Class 9 Extra Questions Long Answer Type

Question 1.
Derive an expression for three equations of motion for uniform accelerated motion graphically.
Answer:
Equation of motion by graphical method
Let us consider a body is moving with acceleration where u is initial velocity and u is final velocity, s is the displacement of object and t is a time interval.

1. υ = u + at
We know that slope of υ – t graph gives acceleration so slope
= a = \(\frac{v-u}{t-0}\)
a = \(\frac{v-u}{t}\)
∴ υ = u + at

2. s = ut + \(\frac{1}{2}\) at²
We know that area under u – t graph gives the displacement.
Area = s = area of triangle CDE + area of rectangle ABCE
s = ut + \(\frac{1}{2}\) x t x (υ – u) from (υ – u = at)
Putting the value of υ – u
s = ut + \(\frac{1}{2}\) at²

3. υ² – u² = 2as
We know that area under υ – t graph gives displacement
Area = s = area of trapezium ABDE
s = \(\frac{1}{2}\) x (υ+u) x t From I (t = \(\frac{υ – u}{a}\))
Putting the value of t.
υ² – u² = 2as

Motion Class 9 Extra Questions HOTS

Question 1.
The distance-time graph of two trains is given below. The trains start simultaneously in the
same direction.
1. How much ahead of A is B when the motion starts?
2. What is the speed of B ?
3. When and where will A catch B?
4. What is the difference between speeds of A and B?

5. Is the speed of both the trains uniform or non-uniform? Justify your answer.

Answer:

1. 100km
2. Speed of B, υ = \(\frac{x_{2}-x_{1}}{t}\) = \(\frac{150-100}{2-0}\) = 25 km/h
3. After 2 hours, A catches B at 2. i.e.,150 km from origin 0.
4. The slope of the distance-time graph of A is greater than that of B. Therefore, the speed of A is greater than
   speed B. Speed of A = Slope of OQ = \(\frac{150}{2}\) = 75 km/h
   Difference between speed of A and B =75 km/h – 25 km/h = 50 km/h
5. The speed of both trains is uniform.

Question 2.
A car starts from rest and moves along the x-axis with constant acceleration 5 ms2 for 8 seconds. If it then continues with constant velocity, what distance will the car cover in 12 seconds since it started from rest?
Answer:
Given,
u = 0, a = 5ms^-2, t₁ = 8s and t₂ = 12s.
Total distance = distance travelled during acceleration + distance travelled during constant velocity
s = s₁ + s₂

For S₁
s₁ = u₁t₁ + \(\frac{1}{2}\) \(a t_{1}^{2}\)
s₁ = \(\frac{1}{2}\) x 5 x (8)²
s₁ = 160 m

For S₁
Applying υ = u + at
υ = 0 + (5 x 8)
u = 40 m/s
s₁ = ut₂
s₂ = 40 x 12
s₂ = 480 m
Total distance, s = s₁ + s₂
s = 160 + 480 = 640m

Question 3.
An object is dropped from rest at a height of 150 m and simultaneously another object is dropped from rest at a height 100 m. What is the difference in their heights after 2s if both the objects drop with the same acceleration? How does the difference in heights vary with time?
Answer:
At t = 0, difference in heights of two stones A and B
= 150 – 100 = 50 m
In t = 2s, distance through which each stone falls is –
s = ut + \(\frac{1}{2}\) at² = 0 x \(\frac{1}{2}\) x 10 x (2)² = 20m
∴ Difference in heights of two stones A and B
= (150 – 20) – (100 – 20) = 50
The difference in heights will remain the same at all times during their fall.

Question 4.
An object starting from rest travels 20 m in the first 2s and 160 m in the next 4s. What will be the velocity after 7s from the start?
Answer:
Given, the object travels 20 m first 2 s and 160 m in the next 4s.
From s = ut + \(\frac{1}{2}\) at²
In first 2 s, s = 20 m
20 = 0 + \(\frac{1}{2}\) a(2)²
20 = 2 a
∴ a = 10 m/s²
Velocity at the end of 2s is υ = u + at
υ = 0 + 10 x 2 = 20 m/s

In next 4 s,
s = ut + \(\frac{1}{2}\) a’t²
160 = 20 x 4 + \(\frac{1}{2}\) a’(4)²
80 = 8 a’
a’ = 10 m/s²

Motion Class 9 Extra Questions Value Based (VBQs)

Question 1.
Sumeet and Jaikishan are close friends. Sumeet is a science graduate and Jaikishan is a commerce graduate. Sumeet finds that while driving on a clear highway, Jaikishan often exceeds the speed limit and argues that there is no harm in doing so when the road is clear. Sumeet does not agree with him and tells him that with an increase in speed, the stopping distance of the car would increase and he would not be able to manage if someone appears suddenly on the way.
Read the above passage and answer the following questions:

1. is Sumeet right in his statement?
2. What values are displayed by Sumeet in his statement?
3. How is stopping distance related to the speed of the vehicle?

Answer:

1. Yes, Sumeet is absolutely right.
2. Sumeet is an intelligent boy and he can apply his knowledge of science in daily life.
3. Stopping distance (velocity)²

Question 2.
Raju and Raman are close friends. One day they went for a picnic. Raju was driving the car. When Raman saw the speedometer, he found that the speed of the car was more than the allowed speed limit. Raman advised Raju to reduce speed to avoid the punishment of Overspeed.
Answer the following questions:

1. What is the function of the speedometer?
2. What values are displayed by Raman?

Answer:

1. Speedometer provides instantaneous speed. B
2. Raman is a careful and law-abiding person.

Question 3.
Three friends Ram, Mohan, and Roy have to reach point B from point A. The path taken by them is shown in the figure.
Answer the following questions:

1. Distinguish between distance and displacement.
2. If all of them travel at the same speed, who will reach first at point B and why?
   

Answer:
1. Distance:

1. It is the actual length of the path covered by a moving body.
2. It is always positive or zero.
3. It is a scalar quantity.

Displacement:

1. It is the shortest measured distance between the initial and final positions.
2. It may be positive, negative, or zero.
3. It is a vector quantity.

2.  Mohan will reach first as he is traveling the shortest path.

In this page, we are providing Force and Laws of Motion Class 9 Extra Questions and Answers Science Chapter 9 pdf download. NCERT Extra Questions for Class 9 Science Chapter 9 Force and Laws of Motion with Answers will help to score more marks in your CBSE Board Exams. https://ncertmcq.com/extra-questions-for-class-9-science/

Class 9 Science Chapter 9 Extra Questions and Answers Force and Laws of Motion

Extra Questions for Class 9 Science Chapter 9 Force and Laws of Motion with Answers Solutions

Force and Laws of Motion Class 9 Extra Questions Very Short Answer Type

Force And Laws Of Motion Class 9 Numericals Extra Questions Question 1.
Define the following terms

1. Force
2. Balanced forces
3. Unbalanced forces
4. Inertia
5. Momentum
6. Conservation of momentum.

Answer:

1. Force: It is an entity which when applied on a body changes or tends to change its state of motion and shape.
2. Balanced forces: When a number of forces acting simultaneously on a body do not bring about any change in the state of rest or of uniform motion along a straight line, then the forces acting on the body are said to be balanced.
3. Unbalanced forces: When a number of forces acting simultaneously on a body bring about a change in its state of rest or of uniform motion along a straight line, then these forces acting on the body are said to be unbalanced forces.
4. Inertia: Inertia is the natural tendency of an object to resist a change in its state of motion or rest.
5. Momentum: Momentum of a body is the product of its mass and velocity.
6. Conservation of momentum: In an isolated system, the total momentum remains conserved.

Force And Laws Of Motion Class 9 Extra Questions Question 2.
Name the physical quantity that measures inertia.
Answer:
Mass of body measures its inertia.

Force And Laws Of Motion Extra Questions Numericals Question 3.
There are three solids made up of aluminum, steel, and wood, of the same shape and same volume. Which of them would have the highest inertia?
Answer:
Steel ball would have the highest inertia as steel is denser than the other two.

Force And Laws Of Motion Class 9 Extra Numericals Question 4.
Name the factors on which the momentum of a body depends.
Answer:

• Mass and
• The velocity of the body.

Class 9 Force And Laws Of Motion Extra Questions Question 5.
Define one newton of force.
Answer:
Force is said to be 1 newton if it produces an acceleration of 1 rn/s² in a body of 1 kg.

Force And Laws Of Motion Extra Questions Question 6.
An object is thrown vertically upwards. What is its momentum at the highest point?
Answer:
Since the velocity at the highest point is zero, so the momentum of the object is zero at the highest point.

Extra Numericals Of Force And Laws Of Motion Class 9 Question 7.
State action and reaction when a bullet is fired from the gun.
Answer:
Action: Force exerted by a spring on the bullet.
Reaction: Force exerted on the gun.

Class 9 Science Chapter 9 Extra Questions And Answers Question 8.
An athlete runs some distance before taking a jump. Why?
Answer:
To gain momentum so that he may jump higher.

Class 9 Physics Chapter 2 Extra Questions Question 9.
Mention any two effects of force.
Answer:

• It changes the state of rest or motion of a body.
• It changes the shape of the body.

Class 9 Force And Laws Of Motion Extra Numericals Question 10.
What happens to the momentum of a body whose velocity is halved?
Answer:
The momentum of the body becomes half.

Class 9 Science Ch 9 Extra Questions Question 11.
Give the magnitude and the direction of the net force acting on the cork of mass 10 g floating on water.
Answer:
Zero.

Class 9 Science Chapter 9 Extra Numericals Question 12.
A car of mass 1000 kg is moving with velocity 5 m/s. Calculate the momentum of the car.
Answer:
Given, mass, m = 1000 kg
Velocity, u = 5 m/s
Momentum, P = mυ
P= 1000 x 5 = 5000kg m/s
P= 5000 kg m/s

Class 9 Physics Force And Laws Of Motion Extra Questions Question 13.
A meteorite burns in the atmosphere before it reaches the Earth’s surface. What happens to the linear momentum?
Answer:
Meteorite burns due to heat produced by frictional force. The linear momentum of the meteorite decreases as a frictional force acts on it.

Class 9th Science Chapter 9 Extra Questions Question 14.
Find the acceleration produced by a force of 2000 N acting on a car of mass 800 kg.
Answer:
Given,
Mass, m =800kg
Force, F = 2000 N
Using F = ma
a = \(\frac{F}{m}\)
a = \(\frac{2000}{800}\) = 2.5 m/s²

Force and Laws of Motion Class 9 Extra Questions Short Answer Type 1

Question 1.
Write down SI unit of (i) force (ii) momentum.
Answer:

• newton (N)
• kg rn/s.

Question 2.
When a person hits a stone, his foot is injured. Why?
Answer:
When a person hits a stone, the stone exerts an equal force on his foot. Due to this force, his foot gets injured.

Question 3.
Why no force is required to move an object with a constant velocity?
Answer;
We know, F = ma
When, velocity is constant, then acceleration, a = 0. Hence, F = 0.

Question 4.
Why is it easier to catch a table tennis ball than a cricket ball, even both are moving with the same velocity?
Answer:
It is easier to catch a table tennis ball because the table tennis ball has less mass (inertia).

Question 5.
Write down the expression for the recoil velocity of the gun.
Answer:
Recoil velocity of gun is given by,
\(\mathrm{V}_{\mathrm{G}}=\frac{m_{b} v_{b}}{\mathrm{M}_{\mathrm{G}}}\)
m_b = mass of bullet
m_G = mass of gun
υ_b = velocity of bullet
V_G = recoil velocity of gun.

Force and Laws of Motion Class 9 Extra Questions Numericals

Question 6.
A car of mass 1000 kg moving with a velocity of 54 km/h hits a wall and comes to rest in 5 seconds. Find the force exerted by the car on the wall.
Answer:
Given, Mass = 1000 kg
Time = 5 s
Initial velocity, u = 54 km/h = 15 m/s
Final velocity, υ = 0 m/s
Time, t = 5s
using, F = m a
F = m\(\left(\frac{v-u}{t}\right)\) = 1000 \(\left(\frac{0-15}{5}\right)\) = -3000N

Question 7.
A body of mass 100g is at rest on a smooth surface. A force of 0.1-newton act on it for 5 seconds. Calculate the distance traveled by the body.
Answer:
Given, Mass of body = 100 g = 0.1 kg
Force, F = 0.1N
Time, t = 5s
Initial velocity, u = 0 m/s
Using formula, F = ma
⇒ a = \(\frac{F}{m}=\frac{0.1}{0.1}\) = 1 m/s²

Using formula, s = ut + at²
s = ut + \(\frac {1}{2}\)at²
⇒ s = 0 + \(\frac {1}{2}\) x 1 x (5)²
∴ s = 12.5 m

Question 8.
A bullet of mass 200 g is fired from a gun of mass 10 kg with a velocity of 100 m/s. Calculate the velocity of recoil.
Answer:
Given, Mass of bullet, m = 200 g = 0.2 kg
Massofgun, M = 10 kg
Velocity of bullet, V_b = 100 m/.s
Recoil velocity of gun, V_G = \(\frac{m v_{b}}{\mathrm{M}}\)
V_G = – \(\frac{0.2 \times 100}{10}\) = 2m/s
Recoil velocity of gun, V_G = 2 m/s

Question 9.
Two spheres of masses 20 g and 40 g moving in a straight line in the same direction with velocities of 3 mIs and 2 m/s respectively. They collide with each other and after the collision, the sphere of mass 20 g moves with a velocity of 2.5 miles. Find the velocity of the second ball after confusion.
Answer:
Given, m₁ = 20 g = 20 x 10^-3 kg
m₁ = 40g = 40g x 10^-3kg
u₁ = 3 m/s
u₂ = 2 m/s
υ₁ = 2.5 m/s
Applying conservation of linear momentum,
m₁u₁ + m₂u₂ = m₁υ₁ + m₂υ₂
20 x 10^-3 x 3 + 40 x 10^-3 x 2 = 20 x 10^-3 x 2.5 + 40 x 10^-3 x υ²
υ₂ = 2.25m/s.

Force and Laws of Motion Class 9 Extra Questions Short Answer Type 2

Question 1.
Newton’s first, second, and third law of motion.
Answer:
Newton’s first law of motion: An object remains in a state of rest or of uniform motion along a straight line unless compelled to change that state by an applied force.

Newton’s second law of motion: The second law of motion states that the rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of the force.

Newton’s third law of motion: According to the third law of motion to every action, there is an equal opposite reaction and they act on two different bodies.

Question 2.
What is momentum? Write its SI unit. Interpret force in terms of momentum. Represent the following graphically.
(a) momentum versus velocity when mass is fixed.
(b) momentum versus mass when velocity is constant.
Answer:
Momentum gives an idea about the quantity of motion contained in a body.
The momentum of (P) of an object is defined as the product of its mass (m) and velocity (υ).
P = mυ
SI unit of momentum is kg ms^-1
Graphs
(a) If m = constant
P ∝ υ

(b) If v = constant
P ∝ m

Question 3.
“Action and reaction are equal and opposite but even they do not cancel each other.” Explain, why?
Answer:
Two equal and opposite forces can cancel each other if they act on the same body. But action and reaction do not act on the same body. They act on two different bodies. Hence cannot cancel each other.

Question 4.
Why are the wheels of vehicles provided with mudguards?
Answer:
The rotating wheels of a vehicle throw out mud sticking to it tangentially due to the inertia of direction. The mudguards stop this mud to fall on another vehicle just moving behind the vehicle.

Question 5.
A car weighing 1600 kg moving with a velocity of 30 mIs retards uniformly coming to rest in 20 seconds. Calculate the
1. Initial and final momentum of the car.
2. Rate of change of linear momentum of the car.
3. Acceleration of the car.
Answer:
Given, mass, m = 1600 kg
Initial velocity, u = 30 m/s
Final velocity, υ = 0 m/s
Time, t = 20s
1. Initial momentum, P_i = mu = 1600 x 30
P_i = 4800 kg m/s
Final momentum, P_f = mυ = 1600 x 0
P_f = 0 kg m/s

2. Rate of change of linear momentum
= \(\frac{P_{f}-P_{i}}{t}\) = \(\frac{0-4800}{20}\) = – 240N
a = \(\frac{v-u}{t}\)

3.  Acceleration,
\(\frac{0 – 30}{20}\)
a = – 1.5 m/s².

Question 6.
Using the second law of motion, derive the relation between force and acceleration. A bullet of 10 g strikes a sand-bag at a speed of 10³ ms² and gets embedded after traveling 5 cm. Calculate
1. the resistive force exerted by the sand on the bullet.
2. the time is taken by the bullet to come to rest.
Answer:
According to the second law of motion,
The rate of change of momentum is directly proportional to the force applied.
F ∝ \(\frac{m(v-u)}{t}\)
F = \(\frac{km(v-u)}{t}\)
∴ F = kma
Take k = 1 in SI system
∴ F = ma

1. Given, mass of bullet, m = 10g = 10 x 10^-3kg
Initial velocity of the bullet, u = 10³m/s
Distance travelled by the bullet, s = 5 cm = 5 x 10^-2 m
Final velocity of the bullet = 0
Using the formula, υ^-2 – u^-2 = 2as
⇒ 0 – (10³)² = 2 x a x 5 x 10^-2

f = m x a = 10 x 10^-3 x (10⁷) = – 10⁵ N

2. From the formula,
υ = u + at
⇒  t = \(\frac {υ – u}{a}\) = \(\frac{0-10^{3}}{-10^{7}}\) = 10^-4 s = 0.0001 s

Question 7.
An object is placed on a rough surface. The external force of 20 N is acting on the body and 10 N frictional force is acting on the body.
Find
1. The net force on an object
2. Acceleration of an object if the mass of an object is 2 kg
3. The velocity of the object after 2 seconds if the object is started from rest.
Answer:
Given,

∴ υ = 10 m/s

Force and Laws of Motion Class 9 Extra Questions Long Answer Type

Question 1.
Explain why?
(a) A cricket player lowers his hands while catching the ball.
(b) The vehicles are fitted with shockers.
(c) A karate player breaks the pile of tiles or bricks with a single blow.
(d) In a high jump athletic event, the athletes are allowed to fall either on a sand bed or cushioned bed.
(e) In a moving car, the drivers and other passengers are advised to wear seat belts.
(f) China and glassware are packed with soft materials.
(g) Athletes are advised to come to a stop slowly after finishing a fast race.
Answer:
(a) if a player does not lower his hands while catching the ball, the time to stop the ball is very small. So a large force has to be applied to reduce the velocity of the ball to zero or to change the momentum of the ball. When a player lowers his hands, the time to stop the ball is increased and hence less force has to be applied to cause the same change in the momentum of the ball. Therefore, the hands of the player are not injured.

(b) The vehicles are fitted with shockers (i.e., springs)
The floor of a vehicle is cónnected to the lower part of the vehicle by springs or shockers. When the vehicle moves over a rough road, the force due to jerks is transmitted to the floor of the vehicle through the shockers. The shockers increase the time of transmission of the force of jerk to reach the floor of the vehicle. Hence less force is experienced by the passengers in the vehicles.

(c) A karate player can break a pile of tiles with a single blow of his hand because he strikes the pile of tiles with his hand very fast, during which the entire linear momentum of the fast-moving hand is reduced to zero in a very short interval of time. This exerts a very large force on the pile of tiles which is sufficient to break them, by a single blow of his hand.

(d) In a high jump athletic event., the athletes are allowed to fall either on a sand bed or cushioned bed: This is done to increase the time of athletes fall to stop after making the high jump, which decreases the rate of change of linear momentum and decreases the impact.

(e) In a moving car, the drivers and other passengers are advised to wear seat belts: When brakes are applied sudden1y, the passengers of the car fall forward due to the inertia of motion. The seat belt worn by passengers of the car prevents them from falling forward suddenly. This enables the entire linear momentum of the passengers to reduce to zero over a long interval of time, hence it prevents injury.

(f) China and glassware are packed with soft material: China and glassware are wrapped in paper before packing to avoid breakage while transporting. During transportation, there may be collisions due to ta jerks of the packed wares. Soft material like paper slows down their rate of change of linear momentum. As a result, the impact is reduced and items are not broken.

(g) Athletes are advised to come to stop slowly after finishing a fast race: By doing so, he decreases the rate of change of linear momentum by increasing the time interval and hence, reducing the impact, which reduces injury.

Question 2.
Explain
(a) How do we swim?
(b) Why does a gun recoil?
(c) It is difficult to walk on sand or ice.
(d) The motion of rocket.
(e) Why does a fireman struggle to hold a hose-pipe?
(f) Rowing of a boat.
(g) When a man jumps out from a boat, the boat moves backward.
(h) Walking of a person.
Answer:
(a) While swimming, a swimmer pushes the water backward with his hands (i.e., he applies force in the backward direction, which is known as action.) The reaction offered by the water to the swimmer pushes him forward.

(b) Recoiling of a gun: When a bullet is fired from a gun, it exerts a forward force on the bullet and the bullet exerts an equal (in magnitude) and opposite (in direction) force on the gun. Due to the high mass of the gun, it moves a little distance backward and gives a backward jerk to the shoulder of the gunman.

(c) It is difficult to walk on sand or ice: When our feet press the sandy ground in the backward direction, the sand gets pushed away and as a result, we get only a small reaction (forward) from the sandy ground making it difficult to walk.

(d) Rocket propulsion Before firing the rocket, the total linear momentum of the system is zero because the rocket is in the state of rest. When it is fired, chemical fuels inside the rocket are burnt and the hot gases are passed through a nozzle with great speed. According to the law of conservation of linear momentum, the total linear momentum after firing must be equal to zero. As the hot gases gain linear momentum to the rear on leaving the rocket, the rocket acquires equal linear momentum in the upward i.e., opposite direction.

(c) A fireman has to make a great effort to hold a hose-pipe to throw a stream of water on the fire to extinguish it. This is because the stream of water rushing through the hose-pipe in the forward direction with a large speed exerts a large force on the hose-pipe in the backward direction which is known as the reaction force. This reaction force tends to move the hose-pipe in the backward direction. Therefore, a fireman struggles to hold the hose-pipe strongly to keep it at rest.

(f) Rowing of a boat: The boatman during the rowing of a boat pushes the water backward with oars (this is an action of the boatman). According to the third law of motion, water exerts an equal (in magnitude) and opposite (in direction) push on the boat which moves it forward (this is a reaction by water). Thus, harder the boatman pushes back the water with oars (i.e., greater is the action), greater is the reaction force exerted by water, and faster the boat moves in the forward direction.

(g) When a man jumps out from a boat, the boat moves backward: When the passengers start jumping out of a rowing boat, they push the boat backward with their feet. The boat exerts an equal (in magnitude) and opposite (in direction) force on passengers in the forward direction which enables them to move forward.

(h) Walking of a person: When a person walks on the ground, he pushes the ground with his foot in the backward direction by pressing the ground. This push is known as the action, According to Newton’s third law of motion, an equal and opposite reaction acts on the foot of the person by the ground. This reaction (force) of the ground on the person pushes him forward.

Force and Laws of Motion Class 9 Extra Questions HOTS

Question 1.
Two balls of the same size but of different materials, rubber and iron are kept on the smooth floor of a moving train. The brakes are applied suddenly to stop the train. Will the balls start rolling? If so, in which direction? Will they move with the same speed? Give reasons for your answer
Answer:
Yes, both the balls will start rolling in the direction opposite to the motion of the train. The speed of two balls will be different as the inertia of the two balls are different.

Question 2.
Two identical bullets are fired on by a light rifle and another by a heavy rifle with the same force. Which rifle will hurt the shoulders more and why?
Answer:
The light rifles will hurt more as the recoil velocity of the light rifle will be greater.

Question 3.
Velocity versus time graph of a ball of mass 50 g rolling on a concrete floor is shown in the figure. Calculate the acceleration and frictional force of the floor on the ball.

Answer:
Given, Mass of ball, m = 50 g = 50 x 10^-3 kg
Acceleration can be calculated by υ – t graph,

= \(\frac{80 \mathrm{m} / \mathrm{s}}{8 \mathrm{s}}\) = – 10 m/s²
a = – 10 m/s²
Friction force, F = ma
F = 50 x 10^-3 x 10
F = 0.5 N

Question 4.
A truck of mass M is moved under a force F. if the truck is then loaded with an object equal to the mass of the truck and the driving force is halved, then how does the acceleration change?
Answer:
Given, Initially
M₁ = M and F₁ = F
Finally
M₂ = 2M and F₂=\(\frac {F}{2}\)
Hence, a₁ = \(\frac{F_{1}}{M_{1}}\)
a₁ = \(\frac{F}{M}\)

and a₂ = \(\frac{F_{2}}{M_{2}}\)
a₂ = \(\frac{\mathrm{F}}{2 \times 2 \mathrm{M}}\) = \(\frac{F}{4M}\)
\(\frac{a_{1}}{a_{2}}=\frac{F / M}{F / 4 M}=4\)
a₂ = \(\frac{a_{1}}{4}\)
Acceleration will become one fourth.

Question 5.
Derive the unit of force using the second law of motion. A force of 5 N produces an acceleration of 8 ms^-2 on a mass m₁ and an acceleration of 24 ms^-2 on a mass m₂. What acceleration would the same force provide if both the masses are tied together?
Answer:
Given, Force, F = 5N
a₁ = 8 m/s²
and a₁ = 24 m/s²
From formula
m₁ = \(\frac{F}{a_{1}}\) = \(\frac{5}{8}\) kg
and m₂ = \(\frac{F}{a_{2}}\) = \(\frac{5}{24}\) kg
When both the masses tied together
a =\(\frac{\mathrm{F}}{m_{1}+m_{2}}\)
a = \(\frac{5}{\frac{5}{8}+\frac{5}{24}}\) = 6m/s²
a = 6m/s²

Force and Laws of Motion Class 9 Extra Questions Value Based (VBQs)

Question 1.
During a cricket match, a new player Ayush injured his hand while catching the ball. His friend Rudra advised him to catch the ball by lowering his hands backward. When Ayush got another chance to catch the ball, he successfully caught the ball without injuring his hands.
Answer the following questions:
(a) A cricket player lowers his hands while catching the ball. Explain why.
(b) Write down the values shown by Rudra.
Answer:
(a) If a player does not lower his hands while catching the ball, the time to stop the ball will be very small. So a large force has to applied to reduce the velocity of the ball to zero or to change the momentum of the ball. When a player lowers his hands, the time to stop the ball is increased and hence less force has to be applied to cause the same change in momentum of the ball. Therefore, the hands of the player are not injured.

(b) Rudra is a good person as he helped his friend Ayush. He is a knowledgeable person.

Question 2.
During servicing his bike Aman advised the mechanic to oil the shockers for its proper functioning.
Answer the following questions:
(a) The vehicles are fitted with shockers. Explain why.
(b) Write down the values shown by Aman.
Answer:
(a) The floor of a vehicle is connected to the lower part of the vehicle by springs or shockers. When a vehicle moves over a rough road, the force due to jerks is transmitted to the floor of the vehicle through the shockers. The shockers increase the time of transmission of the force of the jerk to reach the floor of the vehicle. Hence less force is experienced by the passengers in the vehicles.
(b) Aman is an intelligent and careful person.

Question 3.
Ranjan advised his son Ayush to wear a seat belt while driving the car.
Answer the following questions
(a) While driving the car, the drivers and other passengers are advised to wear seat belts. Explain why.
(b) Write down the values shown by Ranjan.
Answer:
(a) When brakes are applied suddenly, the passengers of the car fall forward due to the inertia of motion. The seat belt worn by passengers of the car prevents them from falling forward suddenly. This enables the entire linear momentum of the passengers to reduce to zero over a long interval of time, hence it prevents injury.
(b) Ranjan is a noble, intelligent, and careful person.

In this page, we are providing Structure of the Atom Class 9 Extra Questions and Answers Science Chapter 4 pdf download. NCERT Extra Questions for Class 9 Science Chapter 4 Structure of the Atom with Answers will help to score more marks in your CBSE Board Exams. https://ncertmcq.com/extra-questions-for-class-9-science/

Class 9 Science Chapter 4 Extra Questions and Answers Structure of the Atom

Extra Questions for Class 9 Science Chapter 4 Structure of the Atom with Answers Solutions

Structure of the Atom Class 9 Extra Questions Very Short Answer Type

Structure Of Atom Class 9 Extra Questions Question 1.
Is it possible for the atom of an element to have one electron, one proton and no neutron? If so, name the element. [NCERT Exemplar]
Answer:
Yes, it is true for hydrogen atom which is represented as \(_{ 1 }^{ 1 }{ H }\)

Class 9 Science Chapter 4 Extra Questions Question 2.
Will ³⁵Cl and ³⁵Cl have different valencies? Justify your answer. [NCERT Exemplar]
Answer:
No, ³⁵Cl and ³⁵Cl are isotopes of an element.

Class 9 Structure Of Atom Extra Questions Question 3.
Why did Rutherford select a gold foil in his a-ray scattering experiment? [NCERT Exemplar]
Answer:
Rutherford selected a gold foil in his a-ray scattering experiment because gold has high malleability.

Structure Of Atom Class 9 Important Questions With Answers Pdf Question 4.
One electron is present in the outermost shell of the atom of an element X. What would be the nature and value of charge on the ion formed if this electron is removed from the outermost shell? [NCERT Exemplar]
Answer:
+ 1.

Extra Questions On Structure Of Atom Class 9 Question 5.
Write any two observations which support the fact that atoms are divisible. [NCERT Exemplar]
Answer:
Discovery of electrons and protons.

Structure Of Atom Extra Questions Question 6.
Write down the electron distribution of chlorine atom. How many electrons are there in a L-shell? (Atomic number of chlorine is 17). [NCERT Exemplar]
Answer:
The electron distribution of chlorine atom is 2, 8, 7 and the L-shell has 8 electrons.

Class 9 Science Chapter 4 Extra Questions And Answers Question 7.
In the atom of an element X, 6 electrons are present in the outermost shell. If it acquires noble gas configuration by accepting requisite number of electrons, then what would be the charge on the ion so formed? [NCERT Exemplar]
Answer:
– 2.

Extra Questions Of Structure Of Atom Class 9 Question 8.
Helium atom has 2 electrons in its valence shell but its valency is not 2, Explain.
Answer:
Helium atom has 2 electrons in its outermost shell and its duplet is complete. Hence the valency is zero.

Structure Of Atom Extra Questions Class 9 Question 9.
An element X has a mass number 4 and atomic number 2. Write the valency of this element.
Answer:
Valency is zero, as K-shell is completely filled.

Class 9 Science Ch 4 Extra Questions Question 10.
Who identified the sub-atomic particle electron?
Answer:
J.J. Thomson.

Class 9 Chapter 4 Science Extra Questions Question 11.
Name the rays discovered by E. Goldstein.
Answer:
Canal rays.

Structure Of An Atom Class 9 Extra Questions Question 12.
Give two examples from everyday life where we use cathode ray tubes.
Answer:
Television picture tube and Fluorescent light tubes.

Structure Of Atom Class 9 Extra Questions And Answers Question 13.
What are the actual values of charge and mass of the electron?
Answer:
Charge = 1.60 x 10^-19 C (one unit negative charge)
Mass = 9.11 x 10^-31 kg (1/1840th of the mass of hydrogen atom).

Chapter 4 Science Class 9 Extra Questions Question 14.
Compare the radius of the nucleus with that of the atom.
Answer:
Radius of the atom is of the order of 10^-10 m while that of the nucleus is of the order of 10^-15 m. Thus, nucleus is 10^-15/10^-10 i.e., 1/100,000^th of the size of the atom.

Ch 4 Science Class 9 Extra Questions Question 15.
Why are Bohr’s orbits called stationary states?
Answer:
According to Bohr, the orbits in which the electrons revolve have fixed energies. Hence, they are called stationary states (stationary means fixed).

Question 16.
Who discovered neutron?
Answer:
Chadwick.

Question 17.
What are nucleons? What is their number called?
Answer:
Protons and neutrons present in the nucleus are collectively called nucleons. Their total number is called ‘mass number’.

Question 18.
What do you mean by ‘Atomic number’?
Answer:
Atomic number of an element is the number of protons present in the nucleus of the atom of that element.

Question 19.
Who discovered the nucleus of the atom?
Answer:
Rutherford.

Question 20.
What is the charge on alpha particle?
Answer:
+ 2.

Question 21.
The mass number of an element is 18. It contains 7 electrons. What is the number of protons and neutrons in it?
Answer:
Number of protons = 7 Number of neutrons = 11 ,

Question 22.
What is the maximum number of electrons that can be present in M-shell?
Answer:
M-shell means 3rd shell for which n = 3. Hence, maximum number of electrons that can be present in M-shell = 2n² = 2 x 3² = 18.

Question 23.
Identify the isotopes out of A, B, C and D? ³³A₁₇, ⁴⁰B₂₀, ³⁷C₁₇, ³⁸D₁₉.
Answer:
³³A₁₄ and ³⁷C₁₇? are isotopes.

Question 24.
Represent the three isotopes of hydrogen and give their names.
Answer:
\(_{ 1 }^{ 1 }{ H }\) (Protium), \(_{ 2 }^{ 1 }{ H }\) (Deuterium), \(_{ 3 }^{ 1 }{ H }\) (Tritium).

Question 25.
How many electrons are present in the species He²⁺ ion? Suggest another name for it.
Answer:
He²⁺ ion has no electrons. It is also called alpha (α) particle.

Question 26.
What is the reason for the identical chemical properties of all the isotopes of an element?
Answer:
Isotopes have identical electronic configuration.

Question 27.
Give one similarity and one difference between a pair of isotopes.
Answer:
They have same number of protons but different number of neutrons in their nuclei.

Question 28.
Give the number of protons and neutrons in an atom of uranium (U-235) used in a nuclear reactor.
Answer:
In nuclear reactor U-235 is used. Atomic number of Uranium is 92.
∴ Number of protons = Atomic number = 92
Number of neutrons = Mass number – Atomic number = 235 – 92 = 143.

Question 29.
Out of proton and neutron, which is heavier?
Answer:
Neutron is slightly heavier (1.675 x 10^-27 kg) than proton (1.67 x 10^-27 kg).

Question 30.
If K and L shells of an atom are completely filled what will be its name?
Answer:
The atom will belong to the noble gas element neon (Ne).

Question 31.
Do isobars have also identical chemical characteristic like isotopes?
Answer:
No, these are not identical because the isobars have different atomic number as well as different electronic configuration.

Question 32.
What is the number of electrons in the valence shell of chlorine (Z = 17)?
Answer:
The electronic distribution of the element is:
K(2), L(8), M(7). This means that the valence shell of chlorine has 7 electrons.

Question 33.
Which radioisotope is used for the treatment of cancer?
Answer:
Radioisotope Co-60 is used for the treatment of cancer.

Question 34.
Out of C-12 and C-14 isotopes of carbon, which is of radioactive nature?
Answer:
C-14 isotope is of radioactive nature.

Question 35.
The electron configuration of an element is: 2(K), 8(L), 5(M). Predict its valency.
Answer:
The valency of the element is 3. It is calculated as: 8 – 5 = 3.

Question 36.
Will \(_{ 12 }^{ 6 }{ C }\) and \(_{ 14 }^{ 6 }{ C }\) have different valencies?
Answer:
Both the species are the isotopes of the same element i.e., the carbon. Since their atomic numbers Eire same, their electronic configurations as well as valencies will also be the same.

Question 37.
Do the elements \(_{ 3 }^{ 1 }{ X }\) and \(_{ 3 }^{ 2 }{ Y }\) represent pair of isotopes?
Answer:
No, they do not because the two elements differ in their atomic numbers. Isotopes have the same atomic numbers.

Structure of the Atom Class 9 Extra Questions Short Answer Type 1

Question 1.
In response to a question, a student stated that in an atom, the number of protons is greater than the number of neutrons, which in turn is greater than the number of electrons. Do you agree with the statement? Justify your answer. [NCERT Exemplar]
Answer:
No, the statement is incorrect. In an atom the number of protons and electrons is always equal.

Question 2.
Calculate the number of neutrons present in the nucleus of an element X which is represented as \(_{ 31 }^{ 15 }{ X }\). [NCERT Exemplar]
Answer:
Mass number = No. of protons + No. of neutrons = 31
∴ Number of neutrons = 31 – number of protons
= 31 – 15
= 16

Question 3.
The atomic number of calcium and argon are 20 and 18 respectively, but the mass number of both these elements is 40. What is the name given to such a pair of elements? [NCERT Exemplar]
Answer:
∴ They are isobars because isobars have different atomic numbers but same mass number.

Question 4.
Why do Helium, Neon and Argon have a zero valency?
Answer:
Helium has two electrons in its only energy shell, while Argon and Neon have 8 electrons in their valence shells. As these have maximum number of electrons in their valence shells, they do not have any tendency to combine with other elements. Hence, they have a valency equal to zero.

Question 5.
What are isobars? Give one example.
Answer:
Isobars are the atoms of different elements which have different atomic numbers but same mass number.
Example is \(_{ 40 }^{ 18 }{ Ar }\), \(_{ 40 }^{ 20 }{ Ca }\) .

Question 6.
What is the number of valence electron in:
(i) Sodium ion (Na⁺)
(ii) Oxide ion (O^2-)?
Answer:
(i) Sodium ion (Na⁺)
No. of electrons: (11 – 1); Electronic configuration = 2, 8.
∴ Na⁺ ion has 8 valence electrons.

(ii) Oxide ion (O^2-)
No. of electrons: (8 + 2) = 10; Electronic configuration = 2, 8.
∴ O^2- ion has 8 valence electrons.

Question 7.
The number of electrons in the outermost ‘L’ shell of an atom is 5.
(a) Write its electronic configuration.
(b) What is its valency and why?
Answer:
(a) 2, 5
(b) 3, because it needs three more electrons to complete its octet.

Question 8.
Write two difference between isobars and isotopes.
Answer:
Isobars

• Same mass number but different atomic numbers.
• Different number of protons.

Isotopes:

• Same atomic number but different mass numbers.
• Same number of protons.

Question 9.
Mention the postulates Neils Bohr put forth to overcome the objections raised against Rutherford’s atomic model.
Answer:
Bohr put forward the following postulates in order to overcome the objections raised against Rutherford s atomic method: .

Only certain special orbits known as discrete orbits of electrons are allowed inside the atom.
While revolving in discrete orbits the electrons do not radiate energy. These orbits or shells are called energy levels.

Question 10.
Given that natural sample of iron has isotopes \(_{ 54 }^{ 28 }{ Fe }\), \(_{ 58 }^{ 28 }{ Fe }\) and \(_{ 57 }^{ 28 }{ Fe }\) in the ratio of 5%, 90% and 5% respectively. What will be the average atomic mass of iron (Fe)?
Answer:
Average atomic mass
= \(\frac { 54 × 5 + 56 × 90 + 57 × 5 }{ 100 }\)
= \(\frac { 270+5040+285 }{ 100 }\)
= 55.95 u.

Question 11.
(a) What are canal rays? Who discovered them?
What is the charge and mass of canal ray?
(b) How are the canal rays different from electron in terms of charge and mass?
Answer:
(a) New radiations in a gas discharge tube which are positively charged. E. Goldstein discovered them. Charge on canal rays is positive and mass is one unit.

(b) Electrons are negatively charged and their mass is approximately 1/2000 of that of canal rays.

Question 12.
The average atomic mass of a sample of an element y is 35.5 u. What are the percentages of isotopes \(_{ 37 }^{ 17 }{ y }\) and \(_{ 35 }^{ 17 }{ y }\), in the sample?
Answer:
Let the % composition of \(_{ 37 }^{ 17 }{ y }\) be x.
Then the % composition of \(_{ 37 }^{ 17 }{ y }\) will be 100 – x
Now,

Question 13.
(i) Write the postulates of Bohr model of atom.
(ii) Draw a sketch of Bohr model of an atom with atomic number 15.
Answer:
(i) Only certain special orbits-discrete orbits of electrons are allowed.

(ii) While revolving in discrete orbits, the electrons do not radiate energy.

Question 14.
List the main differences between an atom and an ion.
Answer:
Atom:

• It is electrically natural.
• The valence shell of atom may or may not have 8 electrons.
• The atoms are less stable.
• It may or may not exist freely in solution.

Ion:

• It has positive or negative charge.
• The valence shell of an ion has 8 electrons.
• The ions are more stable.
• It can exist freely in solution.

Question 15.
An ion has one neutron more than the number of protons but has one electron less than the number of protons. Which two ions are possible which satisfy this condition? Explain.
Answer:
(i) Na⁺ ion, because it has atomic number = 11 and mass number = 23. Thus, no. of protons = 11, no. of neutrons = 23 – 11 = 12 and number of electrons = 11 – 1 = 10.

(ii) K⁺ ion, because it has atomic number = 19 and mass number = 39. Thus, no. of protons = 19, No. of neutrons = 39 – 19 = 20 and no. of electrons = 19 – 1 = 18.

Question 16.
Give the main points of Dalton’s atomic theory.
Answer:

• All matter is made up of a large number of extremely small indivisible particles called atoms.
• Atoms of the different elements are different.
• Atom is the smallest unit of matter which takes part in a chemical reaction.
• Atoms can neither be created nor be destroyed.

Question 17.
The number of electrons, protons and neutrons in a species are equal to 18, 16 and 16 respectively. Assign proper symbol of the species.
Answer:
Number of electrons present = 18
Number of neutrons present = 16
Atomic number of the element = 16
The element with atomic number 16 is sulphur (S). Since it has 18 electrons and not 16, it is therefore, an anion (S^2- ion).

Question 18.
An element with mass number 81 contains 31.7% more neutrons as compared to protons. Assign the atomic symbol. [NCERT Exemplar]
Answer:
We know
Mass number = No. of protons + No. of neutrons = 81
i.e., p + n = 81
Let number of protons = x

Structure of the Atom Class 9 Extra Questions Short Answer Type 2

Question 1.
Show diagrammatically the electron distributions in a sodium atom and a sodium ion and also given their atomic number. [NCERT Exemplar]
Answer:

Since the atomic number of sodium atom is 11, it has 11 electrons. A positively charged sodium ion (Na⁺) is formed by the removal of one electron from a sodium atom. So, a sodium ion has 11 – 1 = 10 electrons. Thus, electronic distribution of sodium ion will be 2, 8. The atomic number of an element is equal to the number of protons in its atom. Since, sodium atom and sodium ion contain the same number of protons, therefore, the atomic number of both is 11.

Question 2.
The ratio of the radii of hydrogen atom and its nucleus is ~ 10⁵. Assuming the atom and the nucleus to be spherical. [NCERT Exemplar]
(i) What will be the ratio of their sizes?
(ii) If atom is represented by planet Earth ‘R_e’ = 6.4 x 10⁵ m, estimate the size of the nucleus.
Answer:
(i) Volume of the sphere = \(\frac { 4 }{ 3 }\) πr³
Let R be the radius of the atom and r be that of the nucleus.

(ii) If the atom is represented by the planet earth (R_e = 6.4 x 10⁶ m) then the radius of the nucleus
would be r_n = \(\frac{\mathrm{R}_{e}}{10^{5}}\)
r_n = \(\frac{6.4 \times 10^{6} \mathrm{m}}{10^{5}}\)
= 6.4 x 10 m = 64 m.

Question 3.
The number of protons, neutrons and electrons in particles from A to E are given below:

(i) Which one is a cation?
(ii) Which one is an anion?
(iii) Which represent pair of isotopes?
Answer:
(i) B is a monovalent cation (B⁺)
(ii) E is a monovalent anion (E^–)
(iii) A and D represent pair of isotopes.

Question 4.
Explain Bohr Bury rules for distribution of electrons into different shells. Write the distribution of electrons in sodium atom (Z = 11).
Answer:
Bohr Bury Rules:

• The maximum no. of electrons present in a shell is given by the formula 2n² (where n is shell number).
• The maximum number of electrons that can be accommodated in the outermost orbit is 8.
• Electrons are not accommodated in a given shell, unless the inner shells are filled.
• Electronic configuration of Na = 2, 8, 1.

Question 5.
Atom A has a mass number 238 and atomic number 92 and atom B has mass number 235 and atomic number 92.
(i) How many protons, atoms A and B have?
(ii) How many neutrons, atoms A and B have?
(iii) Are atoms A and B isotopes of the same element? How?
Answer:
(i) Protons in atoms A and B = 92
(ii) Neutrons in atoms A and B = 146 and 143
(iii) Yes, atom A and B are isotopes of the element since they have the same atomic number or same electronic configuration.

Question 6.
State three features of the nuclear model of an atom put forward by Rutherford.
Answer:

1. There is a positively charged centre in an atom called the nucleus. Nearly, all the mass of an atom resides in the nucleus.
2. The electrons revolve around the nucleus in well-defined orbits.
3. The size of the nucleus is very small as compared to the size of the atom.

Question 7.
The nucleus of an atom is found to have a total mass of nearly 20.088 x 10^-27 kg and a total charge of 9.612 x 10^-19 coulombs. Calculate the atomic number and mass number of the atom. Name the element.
Answer:
Mass of a nucleon (proton or neutron)
= 1.674 x 10^-27 kg
Total mass of nucleus = 20.088 x 10^-27 kg
∴ No. of nucleons (protons + neutrons) present in the nucleus
= \(\frac{20.088 \times 10^{-27}}{1.674 \times 10^{-27}}\) = 12
∴ Mass number = 12u.
Charge on one proton = 1.602 x 10^-19 coulombs; Total charge on the nuclear = 9.612 x 10^-19
∴ No.of protons in the nucleus
= \(\frac{9.612 \times 10^{-19}}{1.602 \times 10^{-19}}\) = 6
Atomic number = 6. Thus, the element is carbon.

Question 8.
Give reasons why?
(а) Atom is electrically neutral.
(b) Atom as a whole is an empty space.
(c) Rutherford model of atom could not provide stability to the nucleus.
Answer:
(a) An atom is electrically neutral because the number of protons and number of electrons in it are equal.

(b) According to Rutherford’s experiment, the size of the nucleus is very small as compared to the size of an atom, therefore, atom as a whole is an empty space.

(c) According to Rutherford, the protons are present inside the nucleus and electrons revolve around the nucleus. According to the elecromagnetic theory, a charged particle moving in a circular path continuously loses energy in the form of electromagnetic radiations and finally falls into the nucleus.

Question 9.
Write the complete symbol for
(i) the nucleus with atomic number 56 and mass number 138.
(ii) the nucleus with atomic number 26 and mass number 55.
(iii) the nucleus with atomic number 4 and mass number 9.
Answer:
(i) The element with atomic number 56 is Ba. Its symbol is \(_{ 138 }^{ 56 }{ Ba }\)

(ii) The element with atomic number 26 is Fe. Its symbol is \(_{ 56 }^{ 26 }{ Fe }\)

(iii) The element with atomic number 4 is Be. Its symbol for \(_{ 9 }^{ 4 }{ Be }\)

Question 10.
How many protons, electrons and neutrons are there in the following nuclei?
(i) \(_{ 17 }^{ 8 }{ O }\)
(ii) \(_{ 25 }^{ 12 }{ Mg }\)
(iii) \(_{ 80 }^{ 35 }{ Br }\)
Answer:
(i) \(_{ 35 }^{ 79 }{ Br }\)
Atomic number, Z = 8
Mass number, A = 17
No. of protons = No. of electrons = Z = 8
No. of neutrons + No. of protons = A
No. of neutrons + 8 = 17
or No. of neutrons = 17 – 8 = 9

(ii) \(_{ 25 }^{ 12 }{ Mg }\)
Atomic number, Z = 12
Mass number, A = 25
No. of protons = No. of electrons = Z = 12
No. of neutrons = A – No. of protons = 25 – 12 = 13.

(iii) \(_{ 80 }^{ 35 }{ Br }\)
Atomic number, Z = 35
Mass number, A = 80
No. of protons = No. of electrons = Z = 35
No. of neutrons = A – No. of protons = 80 – 35 = 45.

Question 11.
An ion with mass number 56 contains 3 units of positive charge and 30.4% more neutrons than electrons. Assign the symbol for the ion.
Answer:
Since the iron carries 3 units of positive charge, it will have 3 electrons less than the number of protons. Let number of electrons = x
No. of protons = x + 3
No. of neutrons = x + \(\frac { x × 30.4 }{ 100 }\)
= x + 0.304x
= 1.304x
Now, No. of protons + No. of neutrons = 56
x + 3 + 1.304 x = 56
2.304 x = 53
x = \(\frac { 53 }{ 2.304 }\) = 23
No. of electrons = 23
No. of protons = 23 + 3 = 26
Symbol = \(_{ 56 }^{ 26 }{ Fe }\)³⁺.

Question 12.
The nuclear radius is of the order of 10^-13 cm while atomic radius is of the order 10^-8 cm. Assuming the nucleus and the atom to be spherical, what fraction of the atomic volume is occupied by the nucleus?
Answer:
The volume of a sphere = 4 πR^3/3 where R is the radius of the sphere.
∴ Volume of the nucleus = 4 πr^3/3 = 4π (10^-13)^3/3 cm³
Similarly,
Volume of the atom = 4 πR^3/3 = 4π (10^-8)^3/3 cm³
∴ Fraction of the volume of atom occupied by the nucleus
= \(\frac{4 \pi\left(10^{-13}\right)^{3} / 3 \mathrm{cm}^{3}}{4 \pi\left(10^{-8}\right)^{3} / 3 \mathrm{cm}^{3}}\)
= 10^-15.

Question 13.
Calculate the number of electrons, protons and neutrons in the following species:
(i) Phosphorus atom
(ii) Phosphide ion (P^3-)
(iii) Magnesium ion (Mg²⁺)
Mass numbers: P = 31; Mg = 24
Atomic numbers: P = 15, Mg = 12.
Answer:
(i) Phosphorus atom
Number of electrons = Atomic number = 15
Number of protons = Atomic number = 15
Number of neutrons = Mass number – Atomic number
= 31 – 15 = 16.

(ii) Phosphide ion (P^3-)
Phosphide ion (P^3-)
= Phosphorus atom + 3 electrons
P^3- = P + 3e^–
Thus, phosphide ion has same number of protons and neutrons as phosphorus atom but has three electrons more.
Number of electrons = 15 + 3 = 18
Number of protons = 15
Number of neutrons = 31 – 15 = 16

(iii) Magnesium ion (Mg²⁺)
Mg²⁺ ion is formed by loss of two electrons by Mg atom. Therefore, it has two electrons less than number of electrons in Mg atom.
Mg²⁺ = Mg – 2e^–
Number of electrons = 12 – 2 = 10
Number of protons = 12
Number of neutrons = (24 – 12) = 12

Structure of the Atom Class 9 Extra Questions Long Answer Type

Question 1.
(a) Enlist the conclusions drawn by Rutherford from his a-ray scattering experiment.
(b) In what way is the Rutherford’s atomic model different from that of Thomson’s atomic model?
Answer:
(a) Rutherford concluded from the a-particle scattering experiment that:

(i) Most of the space inside the atom is empty because the a-particles passed through the gold foil without getting deflected.

(ii) Very few particles were deflected from their path, indicating that the positive charge of the atom occupies very little space.

(iii) A very small fraction of a-particles were deflected by 180°, indicating that all the positive charges and mass of the gold atom were concentrated in a very small volume within the atom.

From the data he also calculated that the radius of the nucleus is about 105 times less than the radius of the atom.

(b) Rutherford proposed a model in which electrons revolve around the nucleus in well-defined orbits. There is a positively charged center in an atom called the nucleus. He also proposed that the size of the nucleus is very small as compared to the size of the atom and nearly all the mass of an atom is centred in the nucleus.

Whereas, Thomson proposed the model of an atom to be similar to a Christmas pudding. The electrons are studded like currants in a positively charged sphere like Christmas pudding and the mass of the atom was supposed to be uniformly distributed.

Question 2.
(a) What were the drawbacks of Rutherford’s model of an atom?
(b) What are the postulates of Bohr’s model of an atom?
Answer:
(a) The orbital revolution of the electron is not excepted to be stable. Any particle in a circular orbit would undergo an acceleration and the charged particles would radiate energy. Thus, the revolving electron would lose energy and finally fall into the nucleus. If this were so, the atom should be highly unstable and hence matter would not exist in the form that we know.

(b) The postulates put forth by Neils Bohr’s about the model of an atom:
(i) Only certain special orbits known as discrete orbits of electrons, are allowed inside the atom.

(ii) While revolving in discrete orbits the electrons do not radiate energy.
These orbits are called energy levels. Energy levels in Em atom are shown by circles.
These orbits are represented by the letters K, L, M, N, …………….. or the numbers, n = 1, 2, 3, 4, ………………

Question 3.
An atom of an element has three electrons in the third shell which is the outermost shell. Write
(a) the electronic configuration
(b) the atomic number
(c) number of protons
(d) valency
(e) the name of the element
(f) its nature whether metal or non-metal.
Answer:
The third shell is M-shell. If the atom of the element has three electrons in the third shell, this means that K and L shells are already filled.
(a) Electronic configuration: 2, 8, 3
(b) Atomic number = No. of electrons = 13
(c) Number of protons = No. of electrons = 13
(d) Valency of the element = 3
(e) The element with Z = 13 is aluminium (Al)
(f) It is a metal.

Question 4.
Answer the following in one line or two:
(a) What is the maximum number of electrons that can be accommodated in the outermost energy shell in an atom?
(b) On the basis of Thomson’s model of an atom, explain how an atom is neutral as a whole.
(c) How many neutrons are present in hydrogen atom?
(d) Do isobars belong to the same element?
(e) An element has five electrons in the M shell which is the outermost shell. Write its electronic configuration.
Answer:
(a) The outermost energy shell in an atom can have a maximum of eight electrons.

(b) According to Thomson’s model of an atom, all the protons in an atom are present in the positively charged sphere while negatively charged electrons are studded in this sphere. Since the electrons and protons are equal in number each carrying one unit charge, the atom as a whole is electrically neutral.

(c) Hydrogen atom has no neutron.

(d) No, isolars belong to different elements since they differ in their atomic numbers.

(e) The electronic configuration of the element is K(2), L(8), M(5).

Question 5.
Explain why did Rutherford select a gold foil in his alpha particle scattering experiments? What observations in a-scattering experiment led Rutherford to make the following observations:
(i) Most of the space in an atom is empty.
(ii) Nucleus is positively charged.
Mention any two drawbacks of Rutherford’s model.
Answer:
Rutherford selected a gold foil because he wanted a very thin layer as possible. This gold foil was about 1000 atoms thick.

(i) As most of the alpha particles passed through the foil undeviated, it means that they did not come across any obstruction in their part. Thus, most of the space in an atom was thought to be empty.

(ii) Very few particles deviated by small angles from their path which suggested that nucleus is positively charged.

The revolution of the electron in any circular orbit is not expected to be stable. Any particle in a circular orbit would undergo acceleration. During acceleration, charged particles would radiate energy. Thus, the revolving electrons would lose energy and finally fall into the nucleus. If this were so, the atom should be highly unstable and matter would not exist in the form that we know. We know that atoms are quite stable.

Question 6.
(a) Why are anode rays called canal rays?
(6) Mention two postulates of J.J. Thomson’s model.
(c) Compare the properties of protons and electrons.
Answer:
(a) The anode rays produced at the anode of the discharge tube are called canal rays because they pass through the holes of the cathode.

(b)

• Atom consists of positively charged sphere and electrons are embedded in it.
• The negative and positive charges are equal in magnitude.

(c) Protons:

• Positively charged.
• Mass of 1 proton is equal to mass of H atom.

Electrons:

• Negatively charged.
• Mass of electron is 1/1840 times that of a proton.

Question 7.
(a) What are isobars?

(b) Atomic number of an element Y is 17.
(i) Write its electronic configuration.
(ii) What is the number of valence electron in Y?
(iii) How many electrons are needed to complete the octet of Y?
(iv) Is it a metal or non-metal?

(c) The valency of Na is 1 and not 7. Give reason.
Answer:
(a) Atoms of different elements with different atomic numbers which have same mass number are called isobars.

(b) (i) 2,8, 7
(ii) 7
(iii) 1
(iv) Non-metal

(c) Electronic configuration of Na is 2, 8,1. It can lose one electron to attain the electronic configuration of neon. Therefore, the valency of Na is 1. The valency of Na may be 7 when it gains 7 electrons in its valence shell, but gain ring 7 electrons is difficult. Therefore, the valency of Na is not 7.

Question 8.
An atom of an element has 2 electrons in the M-shell i.e., third shell. What will be the atomic number of this element? Name this element. Find the valency of this element. Also, find the number of neutrons in the atom of this element.
Answer:
(i) Atomic number is 12

(ii) Element is magnesium.
(iii) Valency is 2 (⁺²)
(iv) No. of neutrons = Atomic mass – No. of protons = 24 – 12 = 12.

Structure of the Atom Class 9 Extra Questions HOTS

Question 1.
What information do you get from the figure given below about the atomic number, mass number and valency of atoms X, Y and Z? Give your answer in a tabular form. [NCERT Exemplar]

Answer:

Question 2.
In the Gold foil experiment of Geiger and Marsdein, that paved the way for Rutherford’s model of an atom, ~ 1.00% of the a-particles were found to deflect at angles > 50°. If one mole of α – particles were bombarded on the gold foil, compute the number of α – particles that would deflect at angles less than 50°. [NCERT Exemplar]
Answer:
% of α – particles deflected more than 50° = 1% of α – particles
% of α – particles deflected less than 50° = 100 – 1 = 99%
Number of α – particles bombarded = 1 mole = 6.022 x 10²³ particles
Number of particles that deflected at an angle less than 50°
= \(\frac { 99 }{ 100 }\) x 6.022 x 10²³
= \(\frac { 596.178 }{ 100 }\) x 10²³
= 5.96 x 10²³.

Question 3.
An ion Y^3- contains 18 electrons and 16 neutrons. Calculate the atomic number and mass number of the element Y. Name the element Y.
Answer:
Number of electrons in Y^3- ion = 18
Since negative charge is formed by gain of electrons by the neutral atom and the number of electrons gained is equal to the number of units of negative charge on the ion.
∴ Number of electrons in the neutral atom = 18-3 =15.
Now, for a neutral atom, Atomic number = Number of protons = Number of electrons.
∴ Atomic number of element Y = 15
Mass number of the element = Number of protons + Number of neutrons = 15 + 16 = 31
The given element Y with atomic number 15 is phosphorus.

Question 4.
The following data represent the distribution of electrons, protons and neutrons in atoms of four elements A, B, C, D.

Answer the following questions:
(a) Give the electronic distribution of element B.
(b) The valency of element A.
(c) The atomic number of element B.
(d) The mass number of element D.
Answer:
(а) Electronic distribution of elements B : 2, 8, 6.
(b) Valency of A is 1(-1).
(c) Atomic number of element B is 16.
(d) Mass number of element D is 39.

Question 5.
Give a reason to explain why:
(a) isotopes of an element show identical chemical properties?
(b) the atomic masses of elements are in fractions?
(c) atoms combine with other atoms?
Answer:
(a) Since all the isotopes of an element have identical electronic configuration containing the same number of valence electrons. Therefore all the isotopes of an element show identical chemical properties.

(b) The fractional atomic masses of elements are due to their isotopes having different masses.

(c) The atoms combine with other atoms to achieve the electronic configuration of the nearest noble gas and thus, become more stable.

Question 6.
(a) Describe the main features of Bohr’s model of an atom. Draw a neat and labelled diagram of energy levels.
(b) Which of the following pairs are isotopes and which are isobars?
(i) \(_{ 58 }^{ 26 }{ A }\), \(_{ 58 }^{ 28 }{ B }\)
(ii) \(_{ 79 }^{ 35 }{ X }\), \(_{ 80 }^{ 35 }{ Y }\)
Give reasons for your choice.
(c) Elements A and B have atomic numbers 18 and 16 respectively. Which of these two would be more reactive and why?
Answer:
(a) Features of Bohr’s Models:
(i) Electrons revolve in certain permitted orbits which are associated with fixed amount of energy. So they are called energy levels (K, L, M, N) or sub-shells.
(ii) As long as electron revolves in the same energy level, they do not lose energy.
(iii) The energy of orbit closest to the nucleus is lowest and farthest away is highest.
(iv) When we supply energy to an electron, it goes to a higher energy level and when it comes back to a lower level it radiates energy.

(b) \(_{ 79 }^{ 35 }{ X }\), \(_{ 80 }^{ 35 }{ Y }\) are isotopes because their atomic no. is same but mass no. is different. \(_{ 58 }^{ 26 }{ A }\), \(_{ 58 }^{ 28 }{ B }\) are iso¬bars, as mass no. is same but atomic no. is different.

(c) B would be more reactive as its electronic configuration is 2, 8, 6 and it requires two more electrons to complete its octet.

Question 7.
Choose the noble gases from the elements shown in the table below:

Answer:

A, B and D have completely filled valence shells, i.e., either 2 or 8 electrons in their valence shells.
∴ A, B and D are noble gases.

Question 8.
The mass number and electronic configuration of five elements A, B, C, D and E are as follows:

(а) Name the elements which has 22 neutrons in nucleus.
(b) What is atomic number of C?
(c) Name the elements which will form most stable ionic bond.
(d) Give the formation of the compound between B and D.
(e) Name the elements which will not take part in chemical combination.
Answer:
(a) E
(b) 11
(c) B and C
(d) DB₄
(e) E

Question 9.
Write the electronic configurations of the following elements and write the number of valence electrons present in it.
(a) \(_{ 14 }^{ 7 }{ N }\)
(b) \(_{ 28 }^{ 14 }{ Si }\)
(c) \(_{ 40 }^{ 20 }{ Ca }\)
(d) \(_{ 40 }^{ 18 }{ Ar }\)
(e) \(_{ 9 }^{ 4 }{ Be }\)
Answer:

Question 10.
Complete the following table.

Answer:
For F atom
Atomic no. = 9 (Give)
No. of electrons = 9
No. of protons = 9
No. of neutrons = 10 (Given)
Mass no. = Z + n = 9 + 10 = 19

For Mg²⁺ ion
No. of protons = 12 (Given)
Atomic no. = 12
No. of electrons = 12 – 2 = 10
Mass no. = 24 (Give)
No. of neutrons = A – Z = 24 – 12 = 12

For S atom
No. of protons = 16 (Given)
Atomic no. = 16
No. of protons = 16
Mass no. = 32 (Given)
No. of neutrons = A – Z = 32 – 16 = 16

For P^3- ion
No. of electrons = 18 (Given)
No. of protons = 18 – 3 = 15
Atomic no. = 15
No. of neutrons = 16 (Given)
Mass no. = Z + n = 15 + 16 = 31

The complete table is as follows:

Note: The value of positive charge on cation shows that the number of electrons in it are less than the number of protons by the same value. Similarly, the value of negative charge on anion shows that the number of electrons in it are more than the number of protons by the same value.

In this page, we are providing Diversity in Living Organisms Class 9 Extra Questions and Answers Science Chapter 7 pdf download. NCERT Extra Questions for Class 9 Science Chapter 7 Diversity in Living Organisms with Answers will help to score more marks in your CBSE Board Exams. https://ncertmcq.com/extra-questions-for-class-9-science/

Class 9 Science Chapter 7 Extra Questions and Answers Diversity in Living Organisms

Extra Questions for Class 9 Science Chapter 7 Diversity in Living Organisms with Answers Solutions

Diversity in Living Organisms Class 9 Extra Questions Very Short Answer Type

Class 9 Science Chapter 7 Extra Question Answer Question 1.
Who proposed the two kingdom classification?
Answer:
Carolus Linnaeus.

Diversity In Living Organisms Class 9 Extra Questions And Answers Question 2.
What is biodiversity?
Answer:
The variety of life forms including plants, animals and microscopic organisms which inhabit this earth constitute biodiversity.

Diversity In Living Organisms Class 9 Questions Question 3.
What is classification?
Answer:
The grouping of organisms on the basis of their similarities and differences is called classification.

Diversity In Living Organisms Class 9 Extra Questions Question 4.
What is the taxonomy?
Answer:
The branch of science which deals with the classification of organisms is called taxonomy.

Diversity In Living Organisms Extra Questions Question 5.
Who proposed the five kingdom system of classification?
Answer:
R.H. Whittaker.

Diversity In Living Organisms Class 9 Questions And Answers Question 6.
Name the fundamental unit of classification.
Or
Which is the lowermost category in the hierarchy of classification?
Answer:
Species.

Diversity In Living Organisms Class 9 Extra Questions And Answers Pdf Question 7.
Give one point of difference between gymnosperms and angiosperms.
Answer:
The seeds of gymnosperms are naked whereas the seeds of angiosperms are enclosed within a fruit.

Diversity In Living Organisms Class 9 Important Questions Question 8.
Name the largest phylum of kingdom Animalia.
Answer:
Arthropoda.

Class 9 Science Ch 7 Extra Questions Question 9.
Name the class to which the sea horse belongs.
Answer:
Sea horse belongs to class Pisces.

Questions On Diversity In Living Organisms Class 9 Question 10.
Which group of plants is referred to as vascular cryptogams?
Answer:
Pteridophytes.

Class 9 Diversity In Living Organisms Extra Questions Question 11.
Which phylum in animial kingdom consists of pseudocoelomate organisms?
Answer:
Nematoda

Class 9 Science Chapter 7 Extra Questions Answers Question 12.
Which group of organisms are called as the ‘Amphibians of plant kingdom*?
Answer:
Bryophytes

Diversity In Living Organisms Class 9 Fill In The Blanks Question 13.
Name the two classes of angiosperms with one example of each.
Answer:
The two classes are –

• Monocots: Wheat
• Dicots: Pea

Diversity In Living Organisms Important Questions Question 14.
Name the division of cryptogams to which algae belong.
Answer:
Thallophyta

Class 9 Diversity In Living Organisms Questions Question 15.
Which is the highest unit of classification?
Answer:
Kingdom

Question 16.
What is the characteristic feature due to which echinoderms are named?
Answer:
Spiny skin (Echino- spiny; derm-skin)

Question 17.
Name the group which comprises of bacteria and blue green algae.
Answer:
Monera

Question 18.
Name an organism which is called saprophyte. Why is it called so?
Answer:
Yeast. It is called so as it feeds on dead and decaying matter to obtain its nutrition.

Question 19.
Identify the kingdom in which the organisms do not have a well-defined nucleus and are not able to show multicellular designs.
Answer:
Monera

Question 20.
Give reason, why blue green algae are classified along with bacteria and placed in the kingdom Monera.
Answer:
As the blue green algae are unicellular prokaryotes like bacteria.

Question 21.
Mention any one characteristic feature of saprophytes.
Answer:
The saprophytes feed on dead and decaying organic matter.

Question 22.
Write one point of difference between monocotyledonous and dicotyledonous plants.
Answer:
Monocots are plants which bear single cotyledon in their seeds. Dicots are the plants which bear two cotyledons in their seeds.

Question 23.
Poriferans have hole or pores all over the body that lead to a system that helps in circulating water to bring in food and oxygen. Name the system.
Answer:
The system is called as the canal system.

Question 24.
State the phylum to which liver fluke and Planaria belong.
Answer:
Phylum Platyhelminthes

Question 25.
Write the type of body cavity and symmetry possessed by nematodes.
Answer:
Body cavity is pseudocoelom and symmetry is bilateral symmetry.

Question 26.
Name one mammal that lays eggs.
Answer:
Platypus

Question 27.
Name the substance which Coelomic cavity of arthropods is filled with. What type of symmetry do they have?
Answer:
Coelomic cavity of arthropods is filled with blood. They show bilateral symmetry.

Question 28.
Name the phylum to which centipede and prawn belong.
Answer:
Phylum Arthropoda

Question 29.
Echinoderms are marine animals. What is their skeleton made up of?
Answer:
Their skeleton is made up of calcium carbonate.

Question 30.
Name one reptile with a four chambered heart.
Answer:
Crocodile

Question 31.
Shyam knew the correct scientific name of mango but did not follow the convention while writing it and wrote it as Mangifera Indica. Rewrite the scientific name as per the convention.
Answer:
Mangifera indica

Question 32.
Rewrite the scientific names correctly:
(a) Panthera tigris
(b) Periplaneta Americana
Answer:
(a) Panthera tigris
(b) Periplaneta americana

Diversity in Living Organisms Class 9 Extra Questions Short Answer Type 1

Question 1.
How can we say that classification of organisms is closely related to their evolution?
Answer:
We can say that classification of organisms is closely related to their evolution because the simple organisms have a primitive body design as they appeared earlier whereas the complex organisms have more advanced body designs as they are more recent. This shows that during the course of evolution more complex body designs were formed from simpler ones.

Question 2.
What is the difference between algae and fungi?
Answer:
Algae:

• Have chlorophyll.
• Autotrophic mode of nutrition.
• Cell wall made of cellulose.
• Food stored in the form of starch.
• Examples: Chlamydomonas, Spirogyra, Ulo-thrix

Fungi:

• Lack chlorophyll.
• Heterotrophic mode of nutrition.
• Cell wall made of chitin.
• Food stored in the form of glycogen.
• Examples: Rhizopus, Agaricus, Yeast

Question 3.
Pick the odd one out and justify your choice by giving reasons:
(a) Moss, Fern, Pinus, Spirogyra
(b) Sea cucumber, Octopus, Feather star, Star fish
Answer:
(a) The odd one out in this case is Pinus as it is a phanerogams having covered reproductive parts whereas the other three are cryptogams which bear hidden reproductive organs.

(b) The odd one out in this case is Octopus as it belongs to phylum Mollusca while others are the members of phylum Echinodermata.

Question 4.
Why were fungi and bacteria considered as plants even though they do not have chlorophyll?
Answer:
Fungi and bacteria were considered as plants as they have cell wall which is a characteristic feature of the plants. So, some earlier classification systems included them under plants.

Question 5.
Why do bryophytes and pteridophytes grow in moist and shady places?
Answer:
Bryophytes and pteridophytes grow in moist and shady places as they need water for their reproduction. Male gametes are carried towards the female gamete by water in order to bring about fertilisation in them.

Question 6.
Which divisions of the plant kingdom are called cryptogams? Why are they called so?
Answer:
Thallophyta, Bryophyla and Pteridophyta are considered as cryptogams. They are called so because they bear hidden and inconspicuous reproductive orgAnswer:

Question 7.
Characteristics of some organisms are given. Identify their group and give one example of each.
(а) Single celled, eukaryotic and photosynthetic
(b) The body is divided into segments, may be unisexual or hermaphrodite
Answer:
(a) Protista: Euglena
(b) Annelida: Earthworm

Question 8.
How do saprophytes get their food? Give one example of saprophyte.
Answer:
Saprophytes derive their nutrition from the dead and decaying materials. For example, Agaricus (Mushroom), Rhizopus (Bread mould), Yeast etc.

Question 9.
What are phanerogams? How are they classified?
Answer:
The phanerogams are the plants which produce seeds and have a well differentiated body with true roots, stem and leaves. They are advanced members of kingdom Plantae. It includes gymnosperms and angiosperms.

Question 10.
What are gymnosperms? Give two examples.
Answer:
The plants which bear naked seeds which are not enclosed in fruit are called gymnosperms. For example, Cycas, Pinus, etc.

Question 11.
Write two peculiar characters of sponges.
Answer:
The two peculiar features of sponges are:
(i) They have pores called ostia all over their body and a single large opening at the top, called osculum which helps to develop a canal system for water movement.

(ii) They have a skeleton made up of calcareous or siliceous spicules or spongin fibres which gives strength and support.

Question 12.
Classify the following in their respective phylum/class: Jellyfish, earthworm, cockroach, rat
Answer:

• Jellyfish: Phylum Coelenterata
• Earthworm: Phylum Annelida
• Cockroach: Phylum Arthropoda
• Rat: Phylum Vertebrata, Class: Mammalia

Question 13.
What are the two peculiar features of phylum Echinodermata?
Answer:
The phylum Echinodermata has organisms which have

• spiny skin
• water vascular system

Question 14.
What are the three germ layers present in the organisms? What are the two groups of organisms on the basis of germ layers?
Answer:
The three germ layers are ectoderm, mesoderm and endoderm. The groups are diploblastic and triploblastic.

Question 15.
How are vertebrates different from the other chordates?
Answer:
The notochord is present at any stage of their life cycle in the case of chordates. In the vertebrates the notochord gets replaced by the vertebral column.

Question 16.
How are pteridophytes are different form Phanerogams? Give one example for each group.
Answer:
Pteridophytes have hidden, inconspicuous reproductive organs example ferns.
Phanerogams have well differentiated reproductive organs which are not hidden, example rose, apple.

Question 17.
(a) Given below are few plant species. Identify the divisions to which they belong and write the major characteristic of each division.
(i) Spirogyra
(ii) Deodar
(iii) Moss
(b) What is the mode of nutrition for all of them?
Answer:
(a) (i) Thallophyta: Plant body is not well differentiated
(ii) Gymnosperms: have naked seeds
(iii) Bryophyta: have rhizoids for absorption of water, have stem-like and leaf-like structures.

(b) All of them are autotrophic organisms.

Question 18.
What do you understand by the term ‘naked embryo’? Name any two divisions in kingdom Plantae that have naked embryo. Give one example of each division.
Answer:
Naked embryo is the term which refers to an embryo which is not borne inside the seed. The pteridophytes and gymnosperms bear naked embryo. For example, Ferns and horsetail are pteridophytes. Pinus and Cycas are gymnosperms.

Question 19.
Write the difference between Gymnosperms and Angiosperms giving example of each type.
Or
What are gymnosperms? Give two characteristics.
Answer:
Gymnosperm:

• Bear naked seeds.
• Are woody, evergreen, perennials.
• Examples: Pinus and Cycas

Angiosperm:

• Bear seeds enclosed in fruit.
• Can be woody, non-woody annual, biennial or perennials.
• Examples: Mango, Neem

Question 20.
Thallophyta, bryophyta and pteridophyta are classified as cryptogams whereas gymnosperms and angiosperms are classified as phanerogams, why?
Answer:
Due to the presence of hidden and inconspicuous reproductive organs, thallophyta, bryophyta and pteridophyta are called as cryptogams. Gymnosperms and angiosperms are phanerogams as they have well developed and distinct reproductive organs, flowers, fruits and seeds.

Question 21.
State reasons for the following:
(а) Platyhelminthes are called so.
(b) Birds have hollow bones.
Answer:
(a) Platyhelminthes are called so because they have a dorsoventrally flattened body.
(b) Presence of hollow bones is an adaptation in birds which helps them to keep low body weight which is helpful in flight.

Question 22.
Identify the phylum of animals by the given characteristics and give an example of each.
(a) The coelomic cavity is blood-filled and the animals have jointed legs.
(b) The animals are called as flatworms and are either free living or parasitic.
Answer:
(a) Phylum arthropoda: eg., cockroach, butterfly, spider, etc.
(b) Phylum Platyhelminthes: Planaria, liver fluke, tapeworm, etc.

Question 23.
Write one point of difference between the following:
(а) Bilateral symmetry and radial symmetry
(b) Annelids and Nematodes
Answer:
(a) Bilateral symmetry – Body can be divided into two exact halves from one plane only.
Radial symmetry – Body can be divided into equal halves from any plane.

(b) Annelids – Have true coelom
Nematodes – Have pseudocoelom.

Question 24.
Give two examples of each:
(а) Egg laying mammals
(b) Organisms with open circulatory system.
Answer:
(а) Duck-billed platypus and Echidna are the egg laying mammals.
(b) Cockroach and Octopus have open circulatory system.

Question 25.
Select the odd one out with respect to classification. Also give reason for your choice: prawn, scorpion, octopus, butterfly.
Answer:
Octopus is the odd one out as it belongs to phylum Mollusca whereas others belong to phylum Arthropoda.

Question 26.
Given below are the two groups of organisms belonging to kingdom Animalia. Write the names of the phylum to which they belong.
(a) Octopus, Pila, Unio
(b) Centipede, prawn, scorpion
Answer:
(а) Octopus, Pila, Unio belong to Phylum Mollusca.
(b) Centipede, prawn, scorpion belong to phylum Arthropoda.

Question 27.
What is binomial nomenclature? Who introduced it?
Answer:
The system of scientific naming of the organism which consists of a generic name and a specific epithet is called as binomial nomenclature. It was introduced by Carolus Linnaeus.

Question 28.
Give two differences between bony fish and cartilaginous fish. Give one example of each.
Answer:
Bony Fish:

• Endoskeleton is made up of bones.
• Operculum covers the gill slits.
• Terminal mouth Example: Rohu, sea horse

Cartilaginous Fish:

• Endoskeleton is made up of cartilage.
• Operculum absent.
• Ventral mouth Example: Shark, saw fish

Question 29.
State any two characteristics of Mammalia. Name two egg laying mammals.
Answer:
Two characteristics of Mammalia are:

• Presence of mammary glands, four chambered heart and are warm-blooded
• Skin has hairs, sweat glands and oil glands Egg laying mammals are platypus and Echidna.

Question 30.
Write appropriate terms for the following.
(a) Animals which are able to maintain a certain body temperature over a wide range of temperature in the environment.
(b) Animals which have pseudocoelom.
Answer:
Kingdom Mammalia: Warm-blooded animals
Phylum Nematoda: Its members have pseudocoelom.

Diversity in Living Organisms Class 9 Extra Questions Short Answer Type 2

Question 1.
Explain the three basic features for grouping all organisms into five major kingdoms.
Answer:
The three basic features for grouping the organisms into five kingdoms are
(i) Cell structure: On the basis of this the two groups are prokaryotes and the eukaryotes which are distinguished on the basis of absence or presence of well defined nuclear membrane.

(ii) Thallus organisation: The organisms are grouped as unicellular or multicellular organisms on the basis of their being composed of a single cell or of many cells respectively.

(iii) Mode of nutrition: The organisms are grouped as autotrophs or heterotrophs on the basis of their ability to synthesise their own food or being dependent on other organisms for their food.

Question 2.
What are the steps in building a hierarchy of classification?
Answer:
The characteristics chosen for developing a hierarchy of classification should start with the characteristic which forms the broadest division and then the next characteristic chosen should be dependent on the previous characteristic and division, besides having its own new characteristic features.

This process should be continued for the next levels in order to build a hierarchy in classification. For example, the classification of organisms into two broad categories prokaryotes and eukaryotes forms the basis of further characteristics on which their classification is based.

Question 3.
Differentiate between Bryophyta and Pteridophyta. Give example of each group.
Or
Write four main features of pteridophyta and give two examples.
Answer:
Bryophyta:

• They are called the ‘amphibians of the plant kingdom’.
• They lack vascular tissues.
• Body is not well-differentiated into true root, stem or leaves.
• The dominant phase or the main plant body is gametophyte (haploid).
• Sporophyte depends upon gametophyte for its support and nutrition.
• Spores are formed in capsule of sporophyte.
• Examples: Liverworts, Mosses

Pteridophyta:

• They are the first land plants.
• They have vascular tissues xylem and phloem.
• Body is well-differentiated into true roots, stem and leaves.
• The dominant phase or the main plant body is sporophyte (diploid).
• Sporophyte and gametophyte are independent structures in them.
• Spores are produced inside the sporangia borne on leaves or cones.
• Examples: Ferns, Horsetail, Marsilea

Question 4.
Name three groups which are placed under Cryptogamae. State and explain two characteristics which are exhibited by each category of these plant bodies.
Answer:
The three groups placed under Cryptogamae are: Thallophyta, Bryophyta and Pteridophyta.

The two characteristic features of cryptogams are:

• They have inconspicuous and hidden reproductive organs.
• They produce naked embryos called spores.

Question 5.
Define the following: (a) Radial symmetry (b) Bilateral symmetry
Answer:
When any plane passing through the central axis can divide the organism into identical halves, it is called radial symmetry, example coelenterates and the adults of Echinoderms.

When only one plane can divide the body of the organism into identical right and left halves, the symmetry is called as bilateral symmetry, example annelids, arthropods and humans.

Question 6.
Give main features of phylum Chordata.
Answer:
The main features of phylum Chordata are presence of:

• Notochord
• Dorsal Central nervous system
• Pharynx perforated by gill slits
• Ventral heart
• A post-anal tail

Question 7.
(a) Write any two features that are present in all chordates.
(b) Write one difference between pseudocoelom and true coelom.
Answer:
(a) The features present in all chordates are:

• Dorsal central nervous system and dorsal nerve cord.
• Triploblastic, coelomate with organ system level of organisation.

(b) If the body cavity of an organism is not lined by mesoderm and the space is filled with vacuolated cells, then the body cavity called pseudocoelom.

Question 8.
Define classification. Give any two of its significance.
Answer:
Grouping of organisms on the basis of their similarities and differences is called classification. Classification is important as it helps to make the study of vast variety of organisms easier and also helps us to understand the inter-relationships which occur among the organisms.

Question 9.
Classify the following plants into different plant divisions. Spirogyra, Fern, Funaria, Pinus, Apple tree, Mustard plant
Answer:
Spirogyra: Thallophyta, Fern: Pteridophyta, Funaria: Bryophyta, Pinus: Gymnosperm, Apple tree: Angiosperm, Mustard plant: Angiosperm

Question 10.
To which group do the following organisms belong and give one reason for each.
(a) Cyanobacteria
(b) Euglena
(c) Ulothrix
Answer:
(a) Cyanobacteria: Kingdom Monera; does not have a well-defined nucleus and lacks membrane bound cell organelles, prokaryotes.

(b) Euglena: Kingdom Protista; are aquatic, unicellular eukaryotes with well-defined nucleus and membrane bound cell organelles.

(c) Ulothrix: Kingdom Plantae, Thallophyta; Have a thalloid body, photosynthetic and eukaryotic.

Question 11.
Why are bryophytes called as ‘Amphibians of plant kingdom9?
Answer:
Bryophytes are called as ‘amphibians of plant kingdom’ because:

• They live in moist, damp places in order to get water from soil either directly or with the help of their rhizoids.
• They require water for the transfer of their gametes and are dependent on water for sexual reproduction.

Question 12.
(а) What is coelom?
(b) Presence of ‘coelom’ in an animal is considered advantageous. Why?
Answer:
(a) Coelom is a body cavity lined by mesodermal cells and lies between the body wall and alimentary canal (gut) of the organism.

(b) The coelom is considered advantageous as it helps to accommodate the various organs of the body in a proper way and gives a greater flexibility to the body of the organism.

Question 13.
(а) Write one characteristic each of amphibia and aves.
(b) Write the name of the class to which following belong:
(i) Sea-horse
(ii) King cobra
Answer:
(a) Amphibia: Can live both on land and in water, slimy to touch, cold blooded with three chambered heart.
Aves: Have forelimbs modified into wings for flight. Body covered with feathers, are warm-blooded with four-chambered heart

(b) Sea-horse: Class Pisces;
King cobra: Class Reptilia

Question 14.
Give the three characteristic features of Class Mammalia.
Answer:
The characteristic features of Class Mammalia are:

• Presence of Mammary glands.
• The skin has hairs.
• Their body has sweat glands and oil glands.
• They have a four-chambered heart, are warm-blooded.

Question 15.
Distinguish between monocots and dicots.
Answer:
Monocots:

• Possess a single cotyledon.
• Have fibrous roots.
• Have parallel venation. Examples: Wheat, Maize

Dicots:

• Possess two cotyledons.
• Have tap root.
• Have reticulate venation. Examples: Pea, gram

Question 16.
(a) What is symbiotic relationship?
(b) Name a symbiotic life form that grows on the bark of tree as large coloured patches.
Answer:
(a) The mutually dependent relationship between two organisms where both are benefitted is called symbiotic relationship.

(b) Lichen is a symbiotic life form that grows on the bark of trees as large coloured patches. It is symbiotic association between fungi and algae.

Question 17.
State the bases of classifying plants and animals into different categories.
Answer:
The bases for classifying animals and plants into different categories are:

• Mode of nutrition – Plants are autotrophic whereas animals heterotrophic.
• Presence or absences of cell wall – Plant cells have cell wall whereas animal cells do not have a cell wall.

Question 18.
(a) Differentiate between Fungi and Plantae.
(b) Mention the basis of classification among plants to different levels.
Answer:
Fungi:

• They are non-chlorophyllous and heterotrophic.
• Their cell wall is made of chitin.
• They are mostly saprophytes or parasites.

Plantae:

• They have chlorophyll and are autotrophic.
• Their cell wall is made of cellulose.
• They are autotrophs.

(b) The basis of classification of plants to different levels is –

• Presence or absence of well-differentiated body tissues
• Presence or absence of a well developed transport system for water, minerals and organic substances.
• Seed bearing ability and presence of seeds enclosed in fruits or not.

Question 19.
Name the group which is called as Amphibian of the plant kingdom. Cite an example of this group, also mention one important feature of the same group.
Answer:
Bryophytes are called amphibians of the plant kingdom, example Marchantia, Funaria.

Characteristic feature: Plant body is thalloid, not well-differentiated and has root-like, stem-like and leaf-like structures.

Question 20.
Identify the following:
(a) Amphibians of the plant kingdom.
(b) Plants with hidden reproductive organs
(c) Mutually benefitted relationship between two organisms.
Answer:
(a) Bryophytes
(b) Phanerogams comprising of Algae, Bryophytes and Pteridophytes.
(c) Symbiotic relationship as shown by algae and fungi in Lichen.

Question 21.
Describe the following:
(a) Lichens
(b) Cryptogams
(c) Phanerogams
Answer:
(a) Lichen is a symbiotic relationship between an algae and fungi.
(b) Cryptogams have hidden or inconspicuous reproductive organs.
(c) Phanerogams have well differentiated reproductive tissues which result in formation of seed.

Question 22.
(а) Which group of plants is known as ‘flowering plants’?
(b) On the basis of seed how is a maize plant different from a pea plant?
Answer:
(a) Angiosperms are called the flowering plants.
(b) Maize is a monocot plant as it bears one cotyledon in its seed whereas pea is a dicot as it has two cotyledons in its seed.

Question 23.
Name the largest group of animals. Write the salient features of this group. Give two examples.
Answer:
Phylum Arthropoda is the largest group of animals. They have jointed legs, bilateral symmetry and a body cavity filled with fluid. For example, Cockroach, spider, butterfly, etc.

Question 24.
What is binomial nomenclature? Who gave it? Write its advantage.
Answer:
The system of scientific naming of organisms which consists of a generic name and a specific epithet is called binomial nomenclature. It was given by Carolus Linnaeus. Its advantage is that it helps in the systematic study and understanding of the living organisms.

Question 25.
List the conventions used for writing a scientific name. What is the importance of scientific name?
Answer:
Convention for writing the scientific names:

• The name of the genus begins with a capital letter.
• The name of the species begins with a small letter.
• When printed, the scientific name is given in italics.
• When written by hand, the genus name and the species name have to be underlined separately.

Common names cannot be used in the same way by the scientist world over and can often result in confusion. To avoid this, a system of scientific names has been proposed.

Question 26.
Write true (T) or false (F)
(а) Whittaker proposed five kingdom classification.
(b) Monera is divided into Archaebacteria and Eubacteria.
(c) Starting from Class, Species comes before the Genus.
(d) Anabaena belongs to the kingdom Monera.
(e) Blue-green algae belongs to the kingdom Protista.
(f) All prokaryotes are classified under Monera.
Answer:
(a) True
(b) True
(c) False
(d) True
(e) False
(f) True

Question 27.
Fill in the blanks:
(a) Fungi shows _______ mode of nutrition.
(b) Cell wall of fungi is made up of _______
(c) Association between blue-green algae and fungi is called as _______
(d) Chemical nature of chitin is _______
(e) _______ has smallest number of organisms with maximum number of similar characters.
(f) Plants without well differentiated stem, root and leaf are kept in _______
(g) _______ are called the amphibians of the plant kingdom.
Answer:
(a) saprophytic
(b) chitin
(c) lichens
(d) Carbohydrate
(e) Species
(f) Thallophyta
(g) Bryophytes

Question 28.
You are provided with the seeds of gram, wheat, rice, pumpkin, maize and pea. Classify them whether they are monocot or dicot.
Answer:
Gram – dicot
Wheat – monocot
Rice – monocot
Pumpkin – dicot
Maize – monocot
Pea -dicot

Question 29.
Match items of column (A) with items of column (B).

Answer:
(a) (ii)
(b) (i)
(c) (iv)
(d) (iii)
(e) (vi)
(f) (u)
(g) (vii)

Question 30.
Match items of column (A) with items of column (B).

Answer:
(a) (iii)
(b) (ii)
(c) (vi)
(d) (i)
(e) (v)
(f) (iv)

Question 31.
Classify the following organisms based on the absence/presence of true coelom (i.e., acoelomate, pseudocoelomate and coelomate) Spongilla, Sea anemone, Planaria, Liver fluke, Wuchereria, Ascaris, Nereis, Earthworm, Scorpion, Birds, Fishes, Horse.
Answer:

• Spongilla: Acoelomate
• Sea anemone: Acoelomate
• Planaria: Acoelomate
• Liver fluke: Acoelomate
• Wuchereria: Pseudocoelomate
• Ascaris: Pseudocoelomate
• Nereis: Coelomate
• Scorpion: Coelomate
• Earthworm: Coelomate
• Birds, Fishes and Horse: Coelomate

Question 32.
Endoskeleton of fishes are made up of cartilage and bone; classify the following fishes as cartilagenous or bony:
Torpedo, Sting ray, Dog fish, Rohu, Angler fish, Exocoetus.
Answer:

• Torpedo: cartilagenous
• Sting ray: cartilagenous
• Dog fish: cartilagenous
• Rohu: bony
• Angler fish: cartilagenous
• Exocoetus: bony

Question 33.
Classify the following based on number of chambers in their heart.
Rohu, Scoliodon, Frog, Salamander, Flying lizard, King Cobra, Crocodile, Ostrich, Pigeon, Bat, Whale
Answer:

• Rohu, Scoliodon: 2 chambered,
• Frog, Salamander, Flying lizard, King Cobra: 3 chambered,
• Crocodile, Ostrich, Pigeon, Bat, Whale: 4 chambered

Question 34.
Classify Rohu, Scolidon, Flying lizard, King Cobra, Frog, Salamander, Ostrich, Pigeon, Bat, Crocodile and Whale into the cold-blooded/warm-blooded animals.
Answer:

• Cold-blooded: Rohu, Scolidon, Flying lizard, King Cobra, Frog, Salamander Crocodile
• Warm-blooded: Ostrich, Pigeon, Bat, Whale

Question 35.
Name two egg laying mammals.
Answer:

• Platypus
• Echidna.

Question 36.
Fill in the blanks:
(а) Five kingdom classification of living organisms is given by _______
(b) Basic smallest unit of classification is _______
(c) Prokaryotes are grouped in Kingdom _______
(d) Paramecium is a Protista because it is an _______
(e) Fungi do not contain _______
(f) A fungus _______ can be seen without microscope.
(g) Common fungi used in preparing bread is _______
(h) Algae and fungi form symbiotic association called _______
Answer:
(a) Robert Whittaker
(b) species
(c) Monera
(d) eukaryotic unicellular organism
(e) chlorophyll
(f) mushrooms
(g) yeast
(h) lichens

Question 37.
Give True (T) and False (F).
(а) Gymnosperms differ from Angiosperms in having covered seed.
(b) Non flowering plants are called Cryptogamae.
(c) Bryophytes have conducting tissue.
(d) Funaria is a moss.
(e) Compound leaves are found in many ferns.
(f) Seeds contain embryo.
Answer:
(a) False
(b) True
(c) False
(d) True
(e) True
(f) True

Question 38.
Give examples for the following.
(a) Bilateral, dorsiventral symmetry is found in _______
(b) Worms causing the disease elephantiasis is _______
(c) Open circulatory system is found in _______ where coelomic cavity is filled with blood.
(d) _______ are known to have pseudocoelom.
Answer:
(a) Liver Fluke
(b) Filarial worms
(c) Arthropods
(d) Nematodes

Question 39.
Label a, b, c and d, given in the figure below. Give the function of (b).
Answer:

(a) Dorsal fin
(b) Caudal fin
(c) Pelvic fin
(d) Pectoral fin
Function of Caudal fins: Caudal fins help in streamlined movement in water.

Question 40.
Fill in the boxes given in figure with appropriate characteristics/plant groups.

(a) Thallophyta
(b) Without specialized vascular tissue
(c) Pteridophyta
(d) Phanerogams
(e) Bear naked seeds
(f) Angiosperm
(g) Have seeds Thallophyta with two cotyledons
(h) Monocots

Diversity in Living Organisms Class 9 Extra Questions Long Answer Type

Question 1.
Explain the various categories of taxonomical hierarchy.
Answer:
The categories in taxonomical hierarchy are

• Kingdom: The highest category of classification
• Phylum (for animals) / Division (for plants): Group of related classes
• Class: Group of related orders.
• Order: Group of related families.
• Family: Group of related genus.
• Genus: Group of related species.
• Species: Group of organisms which can interbreed among themselves to produce a fertile offspring.

Question 2.
(a) Draw labelled diagrams of three protozoa.
(b) Euglena is a dual organism. Why?
Answer:
(a)

(b) Euglena is a dual organism as:

• It does not have a cell wall and behaves as a heterotrophic organism in the absence of sunlight.
• It contains chloroplast and can perform photosynthesis and behaves as autotroph in the presence of sunlight.

Question 3.
Mention the class to which they belong and give one characteristic feature of each. Frog, fish, lizard, pigeon, bat.
Answer:
(i) Fish: Class Pisces; Aquatic, respiration with gills, moist scales present on the body, two-chambered heart, cold-blooded

(ii) Frog: Class Amphibia; Can live both on land and in water, cold-blooded, three-chambered heart, slimy to touch

(iii) Lizard: Class Reptilia; Cold-blooded, three-chambered heart, hard covering present on eggs to prevent from desiccation

(iv) Pigeon: Class Aves; Forelimbs modified into wings for flight and have feathers, have beak, warm-blooded, four-chambered heart

(v) Bat: Class Mammalia; has mammary glands, warm-blooded, four-chambered heart.

Question 4.
(i) Draw a neat labelled diagram of Hydra.
(ii) Label mesoglea and gastro-vascular cavity.
(iii) Name the group of animals it belongs to.
(iv) Name one species of this group that lives in colonies.
Answer:
(i) and (ii)-See figure

(iii) Phylum Coelenterata
(iv) Corals live in colonies.

Question 5.
Write one difference for each of the following pairs:
(i) Thallophyta and Bryophyta
(ii) Nematoda and Annelida
(iii) Amphibians and Reptiles
Answer:
(i)

• Thallophyta Bryophyta – Plant body is not well differentiated into root, stem and leaves. It is a thalloid example – Spirogyra.
• Bryophyta – Plant body slightly more differentiated than Thallophyta with root-like, stem-like and leaf-like structures, called as Amphibians of the plant kingdom.

(ii)

• Nematoda – Called as roundworms, bilaterally symmetrical having pseudocoelom, example Ascaris
• Annelida – Have a metamerically segmented body and a true coelom, example Earthworm

(iii) Amphibians

• Can live both in land as well as water.
• Lack scales on body and have slimy skin.
• Lay eggs in water.
• Eggs are devoid of tough covering.

Reptiles:

• Most of them are terrestrial animals.
• Have dry scales on body.
• Lay their eggs mostly on land.
• Eggs have a tough covering to protect from drying.

Question 6.
(a) In which two ways are amphibians different from fishes?
(b) Identify the phylum of organisms having the characteristics:
(i) Pore bearing animals and radial symmetry
(ii) Body spiny and radial symmetry
(c) Why do gymnosperms not require water for fertilisation?
Answer:
(a) Amphibians can live both on land as well as water, have three-chambered heart and have lungs for respiration in adult stage.
Fishes are aquatic, have two-chambered heart and have gills for respiration.

(b) (i) Phylum Porifera
(ii) Phylum Echinodermata

(c) Gymnosperms do not require water for fertilisation as they bear pollen grains which are carried away by agents like wind to cause pollination.

Question 7.
Give four features of phylum Coelenterata. Give two examples.
Answer:
The four distinguishing features of phylum Coelenterata are:

• They have a radially symmetrical body.
• The body is made of two layers of cells, so called diploblastic.
• Has tentacles which surround their mouth. Tentacles bear cnidoblasts, stinging cells.
• They have a characteristic cavity called as coelenteron.
• They are solitary like Hydra and can be colonial like Obelia. example Hydra, Obelia, Jelly fish.

Question 8.
List the convention that is followed while writing the scientific names. Give scientific name of Mango and Tiger.
Answer:
The conventions followed while writing the scientific names are:

• The name of the genus begins with a capital letter.
• The name of the species begins with a small letter.
• When printed, the scientific name is given in italics.
• When written by hand, the genus name and the species name have to be underlined separately.

Scientific name of Mango is Mangifera indica and of Tiger is Panthera tigris.

Question 9.
Enlist the features of organisms placed in Protista. Give two examples.
Answer:
The members of the kingdom Protista have the following features:

• All of them are unicellular and eukaryotic.
• Their mode of nutrition is either autotrophic or heterotrophic.
• They are usually aquatic but some of them are parasitic.
• Have cilia, flagella or pseudopodia for movement. example Amoeba, Plasmodium

Question 10.
Give the general characteristics of fungi. Give two examples.
Answer:
The general characteristics of fungi are:

• They are heterotrophic organisms which can occur as saprophytes, parasites or symbionts.
• Their cell wall is made up of chitin and lack chlorophyll.
• Food is stored in the form of glycogen in them instead of starch as stored in plants.
• They are eukaryotes as they have membrane bound nucleus.
• For example: Yeast, Rhizopus, Agaricus, Penicillium, etc.

Question 11.
What are the five kingdoms of Whittaker? Give the most important characteristic feature of each kingdom.
Answer:
The five kingdoms proposed by R. H. Whittaker comprises of – Monera, Protista, Fungi, Plantae and Animalia.

• Kingdom Monera: Unicellular, prokaryotes
• Kingdom Protista: Unicellular eukaryotes
• Kingdom Fungi: Non-photosynthetic, chlorophyll absent, heterotrophic nutrition
• Kingdom Plantae: Chlorophyll bearing, photosynthetic autotrophs
• Kingdom Animalia: Heterotrophic nutrition, cell wall absent

Question 12.
(a) To which group do algae belong? Write one characteristic of the division. Give two examples.
(b) Name the group:
(i) Which includes unicellular eukaryotic organisms
(ii) In which mode of nutrition is saprophytic.
(iii) In which seeds are not enclosed in fruits.
(c) Classify flowering plants on the basis of number of cotyledons present in the seed.
Answer:
(a) Algae are members of division Thallophyta. Characteristic – Aquatic, chlorophyll bearing autotrophs.

(b) (i) Protista
(ii) Fungi
(iii) Gymnosperms

(c) The flowering plants are classified as monocots and dicots on the basis of presence of one cotyledon or two cotyledon respectively.

Question 13.
List three groups of plants and tell which plants are referred to as vascular plants? Also mention out of these which group is further classified on the basis of number of cotyledon? State its two characteristics.
Answer:
The pteridophytes, gymnosperms and angiosperms are the vascular plants. Out of these three, angiosperms are classified on the basis of number of cotyledon as – monocots having one cotyledon and dicots having two cotyledons.

Characteristic features of angiosperms are:

• Their seeds are enclosed within fruit.
• Embryo bears the cotyledons also called seed leaves which provide nutrition to the young plant/seedling on the germination of the seed.

Question 14.
(a) On what basis does the embryo of cryptogam differ from that of phanerogams?
(b) Describe the feature that divides the angiosperms into two groups.
(c) State the two sub-groups of angiosperms.
Answer:
(a) Cryptogams bear naked embryos whereas the phanerogams have embryos which are enclosed in seed.
(b) The feature that divides the angiosperms into two groups is the number of cotyledons present in their embryo.
(c) The two sub-groups of angiosperms are monocots (bear single cotyledon) and dicots (have two cotyledons).

Question 15.
Draw a neat diagram of Spirogyra and label the following parts:
(a) Outermost layer of the cell
(b) Organelle that performs the function of photosynthesis
(c) Jelly-like substance in the cell where all organelles are suspended.
(d) Dark coloured and dot-like structure generally present in the centre of the cell.
Answer:

(а) Outermost layer of the cell – Cell wall
(b) Organelle that performs the function of photosynthesis – Chloroplast
(c) Jelly-like substance in the cell where all organelles are suspended – Cytoplasm
(d) Dark coloured and dot-like structure generally present in the centre of the cell – Nucleus

Question 16.
Thallophyta, bryophyta and pteridophyta are called as ‘Cryptogams’. Gymnosperms and Angiosperms are called as ‘phanerogams’. Discuss why. Draw one example of Gymnosperm.
Answer:
Thallophyta, bryophyta and pteridophyta are called as ‘Cryptogams’ because they have hidden or inconspicuous reproductive organs. Spores are formed in them instead of seeds. Gymnosperms and Angiosperms are called as ‘phanerogams’ as they have well differentiated reproductive tissue/organs. Seed harbours the embryo and provides it nourishment too.

Question 17.
Define the terms and give one example of each
(a) Bilateral symmetry
(b) Coelom
(c) Triploblastic
Answer:
(a) If the organism can be divided exactly into two halves from one median plane only, the symmetry is called bilateral symmetry, example liver fluke.

(b) The internal body cavity present between visceral organs and body wall in which well developed organs can be accommodated is called as coelom, example butterfly.

(c) The organisms who have three embryonic layers are called as triploblastic organisms example star fish.

Question 18.
You are given leech, Nereis, Scolopendra, prawn and scorpion; and all have segmented body organisation. Will you classify them in one group? If no, give the important characters based on which you will separate these organisms into different groups.
Answer:
No, all the organisms given in the question do not belong to one group.

Leech and Nereis belong to phylum Annelida because they have metamerically segmented body i.e., body is divided into many segments internally by septa. Body segments are lined up one after the other from head to tail.

The characteristic identifying feature of Scolopendra, prawn and scorpion are the jointed legs and open circulating system due to which they are placed in phylum Arthropoda.

Question 19.
Which organism is more complex and evolved among Bacteria, Mushroom and Mango tree? Give reasons.
Answer:
Mango tree is more complex and evolved because, it is eukaryotic, autotrophic, terrestrial sporophyte with covered seed. Bacteria is unicellular prokaryote and fungi are the heterotrophic, simple thallophyte with no tissue systems.

Question 20.
Differentiate between flying lizard and bird. Draw the diagram.
Answer:
Flying lizard belongs to the group reptiles and is characterised as cold-blooded, body covered with scales and have three-chambered heart, while birds belong to group aves and are characterised as warm¬blooded, having feather covered body, forelimbs modified as wings and having four-chambered heart.

Question 21.
List out some common features in cat, rat and bat.
Answer:
Bat, rat and cat belong to the class Mammalia and have following common features:
(а) All have notochord at some stage of their life cycle.
(b) All are warm-blooded:
(c) All have four-chambered heart.
(d) All have skin covered with hair and with sweat and oil glands.

Question 22.
Why do we keep both snake and turtle in the same class?
Answer:
Because both are –

• Cold-blooded
• Have scales
• Breathe through lungs
• Have three-chambered heart
• They lay eggs with tough covering.

Diversity in Living Organisms Class 9 Extra Questions HOTS

Question 1.
Which group among the Amphibia and Pisces is more advanced and why?
Answer:
The amphibians are more advanced than the Pisces as

• Amphibians can survive both on land as well as in water whereas the members of Pisces can survive only in water.
• Amphibians have a three-chambered heart compared to the two-chambered heart present in the Pisces.
• Amphibians have the ability to respire through lungs but fishes respire through gills.

Question 2.
The protozoans have been included in Protista and not in kingdom Animalia. Give reason.
Answer:
Protozoans are unicellular, eukaryotes so they have been kept in the Kingdom Protista comprising of only the unicellular, eukaryotic organisms. Kingdom Animalia consists of multicellular eukaryotes.

Question 3.
Three types of animal specimen were collected by Rajeev and labelled as A, B and C. The specimen A had slimy skin, respired through lungs, B had dry scales with eggs having tough covering and the specimen C had moist scales with terminal mouth. Identify the class to which the specimens belong.
Answer:
A: Amphibia
B: Reptilia
C: Pisces

Question 4.
While playing near a pond Anmol experienced a pain on his feet. He saw a black coloured organism with metamerically segmented body was clinging to his foot and trying to suck blood from his foot. On the basis of this identify the organism and the phylum to which it may belong to. Name two other members of the phylum to which this organism belongs.
Answer:

• Organism: Leech
• Phylum: Annelida
• Other members: Nereis, Earthworm

Question 5.
Shobha went for a school trip and was shown some organisms which were told by their teachers as the members of the second largest phylum of kingdom Animalia. The organisms had a shell on their body and moved around with their muscular foot. Name the phylum to which the mentioned organism will belong. Give one more characteristic feature and two examples of such organisms.
Answer:
Phylum : Mollusca
Feature : Reduced Coelomic cavity
Examples : Snails and mussels

Question 6.
Three types of plant specimen were observed by Renu and labelled as A, B and C. The specimen A had green colour with undifferentiated thalloid body, B had well differentiated body which formed spores and had a vascular system and the specimen C had cones which had seeds but no fruits were formed in them. Identify the class to which the specimens belong.
Answer:
A: Thallophyta
B: Pteridophyta
C: Gymnosperms

Diversity in Living Organisms Class 9 Extra Questions Value Based (VBQs)

Question 1.
Reena read an article in newspaper regarding the problems caused by the chemical fertilisers. She surfed through the internet and came to know that certain blue-green algae are a good source of fertilisers. She advised the farmers of the area to use them and helped them to stop using chemical fertilisers.
(a) Which group comprises of the blue-green algae?
(b) How do these blue-green algae increase soil fertility?
(c) What are the characteristic features of the group to which they belong?
(d) What values are shown by Reena by her work?
Answer:
(a) Kingdom Monera
(b) They fix atmospheric nitrogen and increase soil fertility
(c) They are unicellular prokaryotes which do not have a well defined nucleus.
(d) Values shown by Reena are concern for environment, helpfulness, eco-friendliness and scientific attitude.

Question 2.
During their trip to a hill station, Shiksha observed some thalloid plants having little differentiation of body which were growing on the moist and damp surface in the form of dense mats. She asked her teacher about them and their role. Her teacher told her which group of organism they were and said that these dense mats were helpful in preventing soil erosion and need water for fertilisation.
(a) What is the probable group of organisms which her teacher would have told her?
(b) What is the peculiar feature of this group of organisms?
(c) Give two examples of members of the group.
(d) What are the values shown by Shiksha?
Answer:
(a) Bryophytes
(b) Can live both on land and in water
(c) Marchantia, Funaria
(d) The values shown by Shiksha are keen observation and scientific attitude.

In this page, we are providing Tissues Class 9 Extra Questions and Answers Science Chapter 6 pdf download. NCERT Extra Questions for Class 9 Science Chapter 6 Tissues with Answers will help to score more marks in your CBSE Board Exams. https://ncertmcq.com/extra-questions-for-class-9-science/

Class 9 Science Chapter 6 Extra Questions and Answers Tissues

Extra Questions for Class 9 Science Chapter 6 Tissues with Answers Solutions

Tissues Class 9 Extra Questions Very Short Answer Type

Class 9 Science Chapter 6 Tissue Extra Question Answer Question 1.
Name any two types of simple permanent plant tissues.
Answer:
The simple permanent tissues of plants are: Parenchyma, collenchyma and sclerenchyma.

Tissues Class 9 Extra Questions With Answers Question 2.
What are blood platelets?
Answer:
Blood platelets are the cell fragments present in the plasma of blood which help in the clotting of blood.

Tissue Class 9 Extra Questions And Answers Question 3.
Name the connective tissue that is found between skin and muscles.
Answer:
Areolar tissue.

Tissues Extra Questions And Answers Question 4.
Name the tissue present in the brain.
Answer:
Nervous tissue which comprises of its basic unit called neurons.

Class 9 Tissue Extra Questions Question 5.
In which of the simple plant tissue, deposition of lignin is found?
Answer:
Sclerenchyma.

Tissues Class 9 Extra Questions Question 6.
Name the basic packing tissue of plant.
Answer:
Parenchyma.

Tissue Extra Questions Class 9 Question 7.
Name the tissue which is present in the veins of leaves.
Answer:
Sclerenchyma.

Class 9 Science Chapter 6 Extra Questions And Answers Question 8.
Why is cork impervious to gases and water?
Answer:
Due to presence of a chemical substance called suberin.

Class 9 Tissues Extra Questions Question 9.
What is the function of phloem?
Answer:
Phloem helps in the transport of food from leaves to the various parts of the plant.

Extra Questions On Tissues Class 9 Question 10.
Which body cell provides resistance against infections?
Answer:
White blood cells (WBC) provide resistance against infections.

Extra Questions Of Tissue Class 9 Question 11.
Which biochemicals compose the solid matrix of cartilage?
Answer:
Proteins and sugars make up the solid matrix of cartilage.

Tissue Class 9 Extra Questions Question 12.
Name the connective tissue which helps in the repair of tissues.
Answer:
Areolar connective tissue helps in the repair of tissue.

Class 9 Science Ch 6 Extra Questions Question 13.
Which connective tissue is specialised for fat storage and acts as heat insulator?
Answer:
Adipose tissue helps in storage of fats and acts as heat insulator.

Tissue Chapter Class 9 Extra Questions Question 14.
Which muscle has spindle-shaped cells?
Answer:
Smooth muscle cells have spindle shaped cells.

Ch 6 Science Class 9 Extra Questions Question 15.
Which meristem is present at growing tips of stems and roots?
Answer:
Apical meristem is present at the growing tips of the stem and roots.

Tissues Class 9 Extra Questions Short Answer Type 1

Question 1.
List any four salient features of meristematic tissue.
Answer:
The salient features of meristematic tissue are:

• This tissue consists of cells which continuously divide to produce new cells.
• The cells of this tissue lack vacuoles.
• The cells of this tissue have dense cytoplasm.
• The cells of this tissue have thin cellulosic cell walls and prominent nuclei.

Question 2.
Write the four elements of xylem.
Answer:
The four elements of xylem are tracheids, vessels, xylem parenchyma and xylem fibres.

Question 3.
How is ligament different from tendons?
Or
Differentiate between tendon and ligament.
Answer:
Ligament is a connective tissue which joins bone to bone and is elastic in nature.

Tendons join bone to muscles and are less elastic as compared to the ligaments.

Question 4.
Write a short note on the different types of meristematic tissue with their location and functions in the plants.
Answer:
The meristematic tissues are classified as apical, lateral and intercalary meristematic tissue based on the region where they are present.

Apical meristem – It is present at the growing tips of stem and roots and results in increase in the length of the stem and the root. Lateral meristem (cambium): It is present on the lateral sides of stem and roots. It helps to increase the girth of the stem or root.

Intercalary meristem – It is present at the base of the leaves or internodes. It helps in the longitudinal growth of plants.

Question 5.
Show the diagrammatic representation of location of lateral meristem and intercalary meristem in plant body.
Answer:

Question 6.
Differentiate between chlorenchyma and aerenchyma.
Or
Write the difference between aerenchyma and chlorenchyma.
Answer:
Chlorenchyma:

• It is a type of parenchyma which contains chlorophyll.
• It helps to perform photosynthesis.
• It is present in green parts of plants like the leaves.

Aerenchyma:

• This type of parenchyma that has large air cavities in it.
• It helps to provide buoyancy to the plants.
• It is present in the aquatic plants, example in their floating leaves.

Question 7.
Write the functions of collenchyma in plants.
Answer:
Collenchyma allows easy bending in various parts of a plant (leaf, stem) without breaking. It also provides mechanical support to plants like in the leaf stalks below the epidermis.

Question 8.
What are the roles of epidermis in plants?
Answer:
The functions of epidermis are:

• Epidermis is usually made up of a single layer of cells and gives protection.
• The epidermis may be thicker in some plants living in dry habitats or often secrete a waxy, water- resistant layer on their outer surface called cutin (chemical substance with waterproof quality) to prevent water loss.
• The epidermis of leaves have small pores called as stomata which help in gaseous exchange and transpiration.
• The epidermal cells of roots bear root hairs that greatly increase the total absorptive surface area of the roots for absorption of water.

Question 9.
Answer the following:
(i) How is the epidermis of the plants living in very dry habitats adapted?
(ii) Write functions of guard cells of stomata in the leaf.
Answer:
(i) The epidermis of plants living in dry habitats may be thicker or often secrete a waxy, water-resistant layer on their outer surface called cutin (chemical substance with waterproof quality) to prevent water loss.

(ii) The guard cells of stomata in the leaf help in gaseous exchange and transpiration.

Question 10.
What is the function of areolar tissues?
Answer:
The functions of areolar tissues are:

• It fills the space inside the organs
• It supports internal organs.
• It helps in repair of tissues.

Question 11.
Determine the location of the following tissues:

1. Unstriated muscle fibres
2. Cuboidal epithelium
3. Adipose tissue
4. Striated muscle fibres

Answer:

1. Unstriated muscle fibres: Present in iris of the eye, ureters, blood vessels, alimentary canal and bronchi of lungs.
2. Cuboidal epithelium: Present in lining of kidney tubules and ducts of salivary glands.
3. Adipose tissue: It is found below the skin and between internal orgAnswer:
4. Striated muscle fibres: It is present in muscles of our limbs

Tissues Class 9 Extra Questions Short Answer Type 2

Question 1.
Explain how the bark of a tree is formed. How does it act as a protective tissue?
Answer:
In the older stem, a strip of secondary meristem replaces the epidermis. The secondary meristem cuts off cells towards outside to form a several-layer thick tissue; This is called the cork or the bark of the tree.

Cells of cork or bark are dead, compactly arranged without intercellular spaces and have a chemical called suberin in their walls that makes them impervious to gases and water. In this way it acts as a protective tissue.

Question 2.
Draw a diagrammatic labelled sketch of stem tip to show location of meristematic tissue. Mention the functions of different types of meristematic tissue.
Answer:

The types of meristematic tissue are:
(i) Apical meristem: It is present at the growing tips of stems and roots and results in increase in the length of the stem and the root.

(ii) Lateral meristem (cambium): It is present on the lateral sides of stems and roots. It helps to increase the girth of the stem or root.

(iii) Intercalary meristem: It is present at the base of the leaves or internodes. It helps in the longitudinal growth of plants.

Question 3.
What are the two main components of blood? Why is blood considered a type of connective tissue?
Answer:
Blood is a special connective tissue consisting of a fluid matrix, plasma, and formed elements. The formed elements are red blood cells (RBCs), white blood cells (WBCs) and blood platelets. Blood is considered as a type of connective tissue as they have the same origin as other types of connective tissue and helps to connect the different parts of the body to facilitate exchange of various components like nutrients and gases.

Question 4.
Give one function of each of the following.
(i) Stomata
(ii) Root nodules
(iii) Cardiac muscle fibres
Answer:
(i) Stomata: Help in exchange of gases in the plants.

(ii) Root nodules: In leguminous plants, the root nodules harbour nitrogen fixing bacteria which convert atmospheric nitrogen into nitrates.

(iii) Cardiac muscle fibres: They help in rhythmic contraction and relaxation of the heart.

Question 5.
Differentiate between bone and cartilage.
Or
Differentiate between bone and cartilage with respect to structure, function and location.
Answer:
Bone:

• Bones have a hard and non-pliable ground substance.
• Its matrix is rich in calcium salts and collagen fibres.
• It is the main tissue that provides structural frame to the body.
• The bone cells (Osteocytes) are present in the spaces called lacunae.
• Bones are present in the limbs and form main skeletal framework of the body.

Cartilage:

• Cartilage is pliable, flexible and resist compression.
• Its matrix is rich in protein called chondrin and sugars.
• It is present in bones of the vertebral column, limbs and hands in adults.
• Cells of this tissue (chondrocytes) are enclosed in small cavities within the matrix secreted by them.
• Cartilage is present in the tip of nose, outer ear joints, between adjacent bones of the vertebral column.

Question 6.
Explain the basic criteria for classification of permanent tissue in plants.
Answer:
The permanent tissues are classified on the basis of the following criteria:

1. Simple (made of one type of cell) or complex (made of more than one type of cells)
2. Cell wall: Thin or thick
3. Type of cell: living or dead
4. Type of function the tissue performs: epidermis is protective, parenchyma is packing or supportive tissue and sclerenchyma makes up conducting tissue.

Question 7.
Identify the given two slides A and B as a parenchyma or sclerenchyma. Sclerenchyma can be identified by which characteristic?

Answer:
Slide A is parenchyma and Slide B is sclerenchyma.
Sclerenchyma can be identified by the type of cells which are long and narrow as the walls are thickened due to presence of lignin.

Question 8.
(i) Identify the given figures.

(ii) Give any two major differences between the structures identified.
(iii) Describe the role performed by these two in the plant body.
Answer:
(i) Structure (A) is a tracheid and structure (B) is a vessel.

(ii) Tracheid:

• Tracheids are elongated or tube-like cells with thick and lignified walls and tapering ends.
• They are in the form of single cells.

Vessel:

• Vessel is a long cylindrical tube-like structure made up of many cells called vessel members.
• They are composed of a number of cells fused together.

(iii) Tracheids and vessels help in vertical transport of water and minerals in the plants. They also help to provide mechanical strength to the plants.

Question 9.
Draw a well labelled diagram of cardiac muscle found in the human body. Write two differences between striated and smooth muscles.
Answer:

Question 10.
Draw a labelled diagram of unstriated muscle tissue and mention its occurrence, features and functions.
Answer:

(i) The cells are long and spindle-shaped.
(ii) They do not have striations.
(iii) Involuntary in nature as they are not under control of our will.
(iv) The cells of smooth muscles are uninucleate.
(v) Smooth muscle fibres are present in iris of the eye, ureters, blood vessels, alimentary canal and bronchi of lungs.

Question 11.
Name the kinds of muscles found in your limbs and lungs. How do they differ from each other structurally and functionally?
Answer:
Striated muscle fibres are found in limbs whereas smooth muscle fibres are present in lungs. The differences in their structure are:
(i) Striated muscle fibres have alternate light and dark bands which are not present in the smooth muscle fibres.

(ii) Striated muscle fibres are cylindrical and multinucleate whereas the smooth muscle fibres are spindle-shaped and uninucleate.

(iii) Striated muscles are voluntary in nature (under control of our will) whereas the smooth muscle fibres are involuntary in nature (not under control of our will).

Question 12.
What are neurons? Where are they found in the body? What function do they perform in the body of an organism?
Answer:
The cells of nervous tissue are called nerve cells or neurons. Neurons are the structural and functional unit of the nervous system. They are found in the brain, spinal cord and nerves.

Their functions are:

• They are highly specialised for transmitting the stimulus from one place to another within the body on being stimulated.
• They help to coordinate the various functions of the body.

Question 13.
Animals of colder regions and fishes of cold water have thicker layer of subcutaneous fat. Describe why?
Answer:
The thick layer of subcutaneous fat acts as insulator and prevents the heat of the body to escape out. The layer of fat acts as a subcutaneous insulation of body for thermoregulation.

Question 14.
Match the column (A) with the column (B).

Answer:
(a) (v)
(b) (iv)
(c) (iii)
(d) (i)
(e) (ii)
(f) (vi)

Question 15.
Match the column (A) with the column (B).

Answer:
(a) (i)
(b) (c)
(d) (iii)
(e) (iv)

Question 16.
If a potted plant is covered with a glass jar, water vapours appear on the wall of glass jar. Explain why.
Answer:
The water is lost by the plant in the form of water vapour due to the process of transpiration. These water vapours appear on the wall of the glass jar.

Question 17.
Name the different components of xylem and draw a living component.
Answer:
Xylem consists of four elements which are:
(a) tracheids
(b) vessels
(c) xylem parenchyma
(d) xylem fibres
The only living component of xylem is xylem parenchyma whose basic structure is shown below:

Question 18.
Draw and identify different elements of phloem.
Answer:
Phloem has four elements called sieve tubes, companion cells, phloem fibres and the phloem parenchyma.

Question 19.
Write true (T) or false (F).
(a) Epithelial tissue is protective tissue in animal body.
(b) The lining of blood vessels, lung alveoli and kidney tubules are all made up of epithelial tissue.
(c) Epithelial cells have a lot of intercellular spaces.
(d) Epithelial layer is permeable layer.
(e) Epithelial layer does not allow regulation of materials between body and external environment.
Answer:
(a) True
(b) True
(c) False
(d) True
(e) False

Question 20.
Differentiate between voluntary and involuntary muscles. Give one example of each type.
Answer:
Voluntary muscles are present in our limbs as skeletal muscles and can be moved by our conscious will whenever we want. Involuntary muscles cannot function on their own. They cannot be controlled by our will or desire. The cardiac muscle and the smooth muscles are involuntary in nature.

Question 21.
Differentiate the following activities on the basis of voluntary (V) or involuntary (IV) muscles.
(a) Jumping of frog
(b) Pumping of the heart
(c) Writing with hand
(d) Movement of chocolate in your intestine
Answer:
(a) (V)
(b) (IV)
(c) (V)
(d) (IV)

Question 22.
Fill in the blanks.
(a) Lining of blood vessels is made up of _______
(b) Lining of small intestine is made up of _______
(c) Lining of kidney tubules is made up of _______
(d) Epithelial cells with cilia are found in _______ of our body.
Answer:
(a) Squamous epithelium
(b) Columnar epithelium
(c) Cuboidal epithelium
(d) Respiratory tract

Question 23.
Water hyacinth floats on water surface. Explain.
Answer:
The parenchyma present in the swollen petiole of water hyacinth is called aerenchyma which has large cavities to provide buoyancy and help them float on the water surface.

Question 24.
Which structure protects the plant body against the invasion of parasites?
Answer:
The epidermis of plants has thick cuticle and waxy substances to prevent the invasion of parasites.

Question 25.
Fill in the blanks.
(а) Cork cells possesses _______on their walls that makes it impervious to gases and water.
(b) _______ have tubular cells with perforated walls and are living in nature.
(c) Bone possesses a hard matrix composed of and _______ and _______
Answer:
(a) suberin
(b) sieve tubes
(c) calcium and phosphorus

Question 26.
Why is epidermis important for the plants?
Answer:
The outermost layer of cells covering an organism is called epidermis. It is usually made up of a single layer of cells and gives protection.

The epidermis may be thicker in some plants living in dry habitats or often secrete a waxy, water- resistant layer on their outer surface called cutin (chemical substance with waterproof quality) to prevent water loss.

The stomata present on the epidermis of leaves helps in gaseous exchange and the loss of water vapour by transpiration.

The epidermal cells of roots bear root hairs that greatly increase the total absorptive surface area of the roots for absorption of water.

Question 27.
Fill in the blanks.
(a) _______ are forms of complex tissue.
(b) _______ have guard cells.
(c) cells of cork contain a chemical called _______
(d) Husk of coconut is made of _______ tissue.
(e) _______ gives flexibility in plants.
(f) _______ and _______ are both conducting tissues.
(g) Xylem transports and _______ and _______ from soil.
(h) Phloem transport from _______ and _______ to other parts of the plant.
Answer:
(a) Xylem and phloem
(b) Stomata
(c) suberin
(d) sclerenchyma
(e) Collenchyma
(g) water; minerals
(h) Food; leaf

Tissues Class 9 Extra Questions Long Answer Type

Question 1.
Differentiate between
(i) Xylem and phloem
(ii) Vessel and sieve tube
(iii) Tracheid and vessel
Answer:
(i) Xylem and phloem –
Xylem:

• Xylem consists of tracheids, vessels, xylem parenchyma and xylem fibres.
• All the cells of xylem except the xylem parenchyma are dead.
• Xylem helps to transport water and minerals.
• The transport is unidirectional through xylem.

Phloem:

• Phloem has four elements called sieve tubes, companion cells, phloem fibres and the phloem parenchyma.
• All cells of phloem are living except the phloem fibres.
• Phloem transports food from leaves to other parts of the plant.
• The transport is bidirectional through the phloem.

(ii) Vessel and sieve tube –
Vessel:

• They are tubular structures having a hollow lumen and composed of dead cells.
• Vessel helps to conduct water and minerals in plants.
• The walls of vessels are lignified.
• They also provide mechanical strength to the plants.
• Their end walls are completely dissolved.

Sieve Tube:

• They are tubular structures having vacuolated cytoplasm and composed of living cells.
• They help to transport food from leaves to other parts of the plant.
• Their walls are not lignified.
• They do not provide mechanical strength to the plants.
• Their end walls have perforations in form of sieve plate.

(iii) Tracheid and vessel _
Tracheid:

• Tracheids are elongated or tube-like cells with thick and lignified walls and tapering ends.
• They are in the form of single cells.
• The inner layers of the cell walls are more thickened.
• They have narrow lumen.
• They have pointed ends.

Vessel:

• Vessel is a long cylindrical tube-like structure made up of many cells called vessel members.
• They are composed of a number of cells fused together.
• Their walls are less thickened.
• They have wide lumen.
• They have blunt ends.

Question 2.
Differentiate between striated, unstriated and cardiac muscle fibres.
Answer:

Question 3.
(i) What is nervous tissue?
(ii) Draw a well labelled diagram of neuron. (Label any 4 parts)
Answer:
Nervous tissue is a tissue made of neurons. It is divided into two parts: the central nervous system (CNS) consisting of the brain and spinal cord; and the peripheral nervous system (PNS) which regulates and controls the various functions and activities of the body.

Question 4.
Write the differences between animal tissue and plant tissue.
Answer:
Plant Tissue:

• The tissue is well differentiated into meristematic tissue and permanent tissue.
• The tissue can grow throughout life due to activity of meristematic tissue.
• They are autotrophic in nature.
• The tissue has more amount of dead tissue which provides mechanical strength to the plants.
• The tissue organisation is comparatively simple.

Animal Tissue:

• The tissue is not much differentiated like the plant tissue.
• The tissue does not show growth throughout life.
• They are heterotrophic in nature.
• The tissue has more amount of living tissue than dead tissue.
• The tissue is complex as it is organised into organs and organ systems.

Question 5.
Write a note on the protective tissue in plants. (Give appropriate diagram also)
Answer:
The protective tissues in plants are epidermis and the cork.
(i) Epidermis: The outermost layer of cells covering an organism is called epidermis. It is usually made up of a single layer of cells and gives protection.

The epidermis may be thicker in some plants living in dry habitats or often secrete a waxy, water- resistant layer on their outer surface called cutin to prevent water loss.

The epidermis of leaves have small pores called stomata which are enclosed by two kidney-shaped cells called guard cells. Stomata help in gaseous exchange and transpiration.

The epidermal cells of roots bear root hairs that greatly increase the total absorptive surface area of the roots for absorption of water.

(ii) Cork: A strip of secondary meristem replaces the epidermis of the older stem and cuts off cells towards compactly arranged without intercellular spaces and have a chemical called suberin in their walls that makes them impervious to gases and water.

Question 6.
Explain the significance of the following:
(i) Hair-like structures on epidermal cells.
(ii) Epidermis has thick waxy coating of cutin in desert plants.
(iii) Small pores in epidermis of leaf.
(iv) Numerous layers of epidermis in cactus.
(v) Presence of a chemical suberin in cork cells.
Answer:
(i) To increase the total absorptive surface area for absorption of water.
(ii) To prevent water loss by transpiration and protection from pathogens.
(iii) To help in gaseous exchange and transpiration.
(iv) To prevent water loss by transpiration.
(v) To make tissue impervious to gases and water.

Question 7.
Differentiate between sclerenchyma and parenchyma tissues. Draw well labelled diagram.
Answer:
Parenchyma:

• Cells are thin walled and thickened with cellulose.
• It is made up of living cells.
• Cells are usually loosely pac ked with large intercellular spaces.
• Helps to store nutrients and water in stem and roots.
• It is called chlorenchyma if it contains chlorophyll and performs photos ynthesis. The parenchyma of
• aquatic plants have large cavities to provide buoyancy to the plants to help them float, it is then called aerenchyma.

Sclerenchyma:

• Cells are thick and thickened with lignin.
• This tissue is made up of dead cells.
• There are no intercellular spaces between the cells.
• Provides strength to the various parts of the plant.
• The cells are long and narrow, make the plant hard and stiff. This tissue provides strength to the plants and is present in stems, around vascular bundles, in the veins of leaves and in the hard covering of seeds and nuts.

Question 8.
Describe the structure and function of different types of epithelial tissues. Draw diagram of each type of epithelial tissue.
Answer:
Epithelial tissues are the covering or protective tissues and cover most organs and cavities in the animal body. These cells are tightly packed, form a continuous sheet and are almost without any intercellular spaces between them. E.g., skin, the lining of the mouth, the lining of blood vessels, lung alveoli and kidney tubules are all made of epithelial tissue.

All epithelium is usually separated from the underlying tissue by an extracellular fibrous basement membrane. The types of epithelium on the basis of their structure and functions are:

(a) Squamous epithelium: Consists of flattened cells. Present in oesophagus and lining of the mouth. Skin epithelial cells are arranged in many layers to prevent wear and tear and are called stratified squamous epithelium.

(b) Columnar epithelium: Has tall or ‘pillar-like’ cells. It forms the inner lining of the intestine.

(c) Cuboidal epithelium: Has cube-shaped cells. It forms the lining of kidney tubules and ducts of salivary glands, where it provides mechanical support.

(d) Ciliated epithelium: Have cilia on the outer surfaces of epithelial cells. The cilia can move and their movement pushes the mucus in the respiratory tract forward to clear it.

(e) Glandular epithelium: Has gland cells which secrete substances at the epithelial surface.

Question 9.
Give reasons for
(a) Meristematic cells have a prominent nucleus and dense cytoplasm but they lack vacuole.
(b) Intercellular spaces are absent in sclerenchymatous tissues.
(c) We get a crunchy and granular feeling, when we chew pear fruit.
(d) Branches of a tree move and bend freely in high wind velocity.
(e) It is difficult to pull out the husk of a coconut tree.
Answer:
(a) Because the meristematic cells are actively dividing cells and there is no need of storage.
(b) Because they have a thick deposition of lignin in them.
(c) Due to the presence of stone cells (sclerenchyma) in the pear fruit.
(d) Due to the presence of collenchyma which provides flexibility to the various parts of the plant.
(e) Due to the sclerenchyma present in the husk of the coconut.

Question 10.
List the characteristics of cork. How are they formed? Mention their role.
Answer:
The characteristics of cork are:

• Cells of cork are dead at maturity.
• These cells are compactly arranged.
• Cells do not possess intercellular spaces.
• Cells possess a chemical substance suberin in their walls.
• They are several layers thick.

A strip of secondary meristem replaces the epidermis of the older stem and cuts off the outside cells to form a several-layer thick cork or the bark of the tree. Cells of cork are dead, compactly arranged without intercellular spaces and have a chemical called suberin in their walls that makes them protective in function and impervious to gases and water.

Question 11.
(a) Differentiate between meristematic and permanent tissues in plants.
(b) Define the process of differentiation.
(c) Name any two simple and two complex permanent tissues in plants.
Answer:
(a) Meristematic tissue:

• This tissue consists of cells which continuously divide to produce new cells.
• They are located at specific regions of the plant, i.e., apical, lateral and intercalary.
• The cells of this tissue are very active, lack vacuoles, have dense cytoplasm, thin cell walls and prominent nuclei.

Permanent tissue:

• Consists of cells which have taken up a specific role and lost the ability to divide.
• They are distributed throughout the plant body.
• They are vacuolated, vary in shape and size. Their cell wall may be thick.

(b) The process of taking up a permanent shape, size, and a function by the cells is called differentiation.

(c) Simple: Parenchyma/collenchyma/sclerenchyma Complex: Phloem/xylem

Tissues Class 9 Extra Questions HOTS

Question 1.
The walls of the sclerenchymatous cells are thickened and have narrow lumen. Which substance thickens it and what is its role?
Answer:
The walls of the sclerenchymatous cells are thickened due to presence of lignin. It helps in providing mechanical strength to the various parts of the plant.

Question 2.
Which type of muscle fibres will contract to remove your hands instantly when you touch a hot object?
Answer:
Striated muscle fibres will contract to remove our hands instantly when we touch a hot object.

Question 3.
Which tissue helps the leaves of lotus plant to float on water? Why?
Answer:
Aerenchyma helps the leaves of lotus plant to float on water. Aerenchyma has large cavities to provide buoyancy to the parts of aquatic plants.

Question 4.
A tissue present in plants helps in storing food and sideways conduction of water. Identify the type of tissue.
Answer:
The tissue is xylem parenchyma.

Question 5.
Which tissue enables the heart to pump blood to various parts of the body? Why?
Answer:
The cardiac muscles help the heart to pump blood to various parts of the body as they show rhythmic contraction and relaxation throughout their life.

Question 6.
What will be the consequence of
(i) removal of blood platelets from blood?
(ii) removal of cutin from the layer of epidermis?
Answer:
(i) Removal of blood platelets from blood will inhibit clotting of blood if an injury occurs and the person may bleed to death.

(ii) Removal of cutin would increase the amount of water loss from the leaves of the plants.

Question 7.
Some actions of our body are under our control but many of them are not under our control. Why is it so?
Answer:
The actions of our body are controlled by our muscles. The voluntary actions are under the control of our will and are caused by the activity of striated muscles, eg., movement of our limbs. The involuntary . actions are not under the control of our will and are performed by the smooth muscles, e.g., the activity of bronchi of lungs. Even the activity of cardiac muscles which helps in the rhythmic contraction and relaxation of heart are involuntary in nature.

Question 8.
Which kind of meristem can help grasses to regenerate parts removed by the grazing herbivores?
Answer:
Intercalary meristem can help grasses to regenerate parts removed by the grazing herbivores.

Question 9.
Name the tissue which replaces the epidermal tissue in older stem and is rich in suberin. What is the function of suberin?
Answer:
Cork is the tissue which replaces the epidermal tissue in older stem and is rich in suberin. Suberin present in the walls of cork cells makes them impervious to gases and water.

Question 10.
The process of transpiration does not occur properly when the leaves are covered by a layer of oily substance. Why? Which other functions will get affected due to this covering?
Answer:
The layer of oily substance will close the stomata present in leaves and this would decrease the rate of transpiration. The rate of exchange of gases decreases and consequently the rate of photosynthesis would also decrease.

Tissues Class 9 Extra Questions Value Based (VBQs)

Question 1.
Raman got injured while playing football. His injured leg started bleeding and his friends immediately rushed to take him to the doctor to give him first aid. The blood flowing from the wound stopped after some time and the doctor applied antiseptic on the wound.
(i) Why did the blood stop flowing after some time from the wound?
(ii) What kind of tissue is blood? Why?
(iii) What values are shown by Raman’s friends?
Answer:
(i) The blood stopped flowing after some time from the wound as the blood platelets present in blood helped in clotting of blood.

(ii) Blood is a connective tissue. Blood is considered as a type of connective tissue as they have the same origin as other types of
connective tissue and helps to connect the different parts of the body.

(iii) The values shown by Raman’s friends are presence of mind, helpful and a caring nature.

Question 2.
During a sports event, Shivani suffered a sprain due to which she was not able to run. Her teacher gave her support and told her that it was due to a ligament tear. She also called the doctor to give treatment to Shivani.
(i) What is a ligament? What kind of tissue is it?
(ii) Which type of fibrous tissue has great strength, limited flexibility and is similar to ligament?
(iii) What values are shown by Shivani’s teacher?
Answer:
(i) Ligament is the connective tissue which connects two bones. It is a kind of connective tissue.

(ii) Tendon is a fibrous tissue that has great strength, limited flexibility and is similar to ligament.

(iii) The values shown by her teacher are knowledge, scientific approach and a caring nature.

Question 3.
Rishi brought an aquatic plant which was floating on the surface to the science laboratory of water. He cut a section of the leaf of the plant and saw a tissue with lot of air cavities in it. He went to his teacher and discussed about the role of the air cavities in the leaves of the aquatic plant.
(i) Which type of tissue present in plants has air cavities?
(ii) What is the role of large air cavities in the leaves of such plants?
(iii) What values are shown by Rishi?
Answer:
(i) Aerenchyma is the tissue present in the plants and has large air cavities.

(ii) The large air cavities in the leaves of such plants help in providing buoyancy to the leaves to help them float on water.

(iii) Rishi shows a scientific attitude, inquisitive nature and empirical approach.

Here we are providing Probability Class 9 Extra Questions Maths Chapter 15 with Answers Solutions, Extra Questions for Class 9 Maths was designed by subject expert teachers. https://ncertmcq.com/extra-questions-for-class-9-maths/

Extra Questions for Class 9 Maths Probability with Answers Solutions

Extra Questions for Class 9 Maths Chapter 15 Probability with Solutions Answers

Probability Class 9 Extra Questions Very Short Answer Type

Probability Class 9 Extra Questions Question 1.
The blood groups of some students of Class IX were surveyed and recorded as below :

If a student is chosen at random, find the probability that he/she has blood group A or AB.
Solution:
Here,
total number of students = 19 + 6 + 13 + 12 = 50
Number of students has blood group A or AB = 19 + 13 = 32
Required probability = \(\frac{38}{50}\) = \(\frac{16}{25}\)

Class 9 Probability Extra Questions Question 2.
A group of 80 students of Class X are selected and asked for their choice of subject to be
taken in Class XI, which is recorded as below :

If a student is chosen at random, find the probability that he/she is a student of either commerce or humanities stream.
Solution:
Here, total number of students = 80
Total number of students of Commerce or Humanities stream = 33
Required probability = \(\frac{33}{80}\)

Probability Extra Questions Class 9 Question 3.
A box contains 50 bolts and 150 nuts. On checking the box, it was found that half of the bolts and half of the nuts are rusted. If one item is chosen at random, find the probability that it is rusted.
Solution:
Total number of nuts and bolts in the box = 150 + 50
= 200
Number of nuts and bolts rusted = \(\frac{1}{2}\) × 200 = 100
P(a rusted nut or bolt) = \(\frac{100}{200}\) = \(\frac{1}{2}\)

Class 9 Maths Chapter 15 Extra Questions Question 4.
A dice is rolled number of times and its outcomes are recorded as below:

Find the probability of getting an odd number.
Solution:
Total number of outcomes = 250
Total number of outcomes of getting odd numbers = 35 + 50 + 53 = 138
∴ P(getting an odd number) = \(\frac{138}{250}\) = \(\frac{69}{125}\)

Extra Questions Of Probability Class 9 Question 5.
The probability of guessing the correct answer to a certain question is \(\frac{x}{2}\) If probability of
not guessing the correct answer is \(\frac{2}{3}\), then find x.
Solution:
Here, probability of guessing the correct answer = \(\frac{x}{2}\)
And probability of not guessing the correct answer = \(\frac{x}{2}\)
Now, \(\frac{x}{2}\) + \(\frac{2}{3}\) = 1
⇒ 3x + 4 = 6
⇒ 3x = 2
⇒ x = \(\frac{2}{3}\)

Extra Questions On Probability Class 9 Question 6.
A bag contains x white, y red and z blue balls. A ball is drawn at the random, then what is the probability of drawing a blue ball.
Solution:
Number of blue balls = Z
Total balls = x + y + Z
∴ P(a blue ball) = \(\frac{z}{x+y+z}\)

Probability Class 9 Extra Questions Short Answer Type 1

Probability Questions For Class 9 Question 1.
750 families with 3 children were selected randomly and the following data recorded:

If a family member is chosen at random, compute the probability that it has :
(i) no boy child
(ii) no girl child
Solution:
(i) P(no boy child) = \(\frac{100}{750}\) = \(\frac{2}{15}\)
and P (no girl child) = \(\frac{120}{750}\) = \(\frac{4}{25}\)

Probability Questions Class 9 Question 2.
If the probability of winning a race of an athlete is \(\frac{1}{6}\) less than the twice the probability of losing the race. Find the probability of winning the race.
Solution:
Let probability of winning the race be p
∴ Probability of losing the race = 1 – p
According to the statement of question, we have
p = 2 (1 – p) – \(\frac{1}{6}\)
⇒ 6p = 12 – 12p – 1
⇒ 18p = 11
⇒ p = \(\frac{11}{18}\) .
Hence, probability of winning the race is \(\frac{11}{18}\).

Questions On Probability Class 9 Question 3.
Three coins are tossed simultaneously 150 times with the following frequencies of different outcomes :

Compute the probability of getting :
(i) At least 2 tails
(ii) Exactly one tail
Solution:
Here, total number of chances = 150
(i) Total number of chances having at least 2 tails = 32 + 63 = 95
∴ Required probability = \(\frac{95}{150}\) = \(\frac{19}{30}\)
(ii) Total number of chances having exactly one tail = 30
∴ Required probability = \(\frac{30}{150}\) = \(\frac{1}{5}\)

Probability Class 9 Extra Questions Short Answer Type 2

Probability Class 9 Extra Questions Pdf Question 1.
The table shows the marks obtained by a student in unit tests out of 50 :

Find the probability that the student get 70% or more in the next unit test. Also, the probability that student get less than 70%.
Solution:
Here, the marks are out of 50, so we first find its percentage (i.e., out of 100)

Total number of outcomes = 5
Probability of getting 70% or more marks = \(\frac{3}{5}\)
Probability of getting less than 70% = \(\frac{2}{5}\)

Class 9 Maths Probability Extra Questions Question 2.
Books are packed in piles each containing 20 books. Thirty five piles were examined for defective books and the results are given in the following table :

One pile was selected at random. What is the probability that it has :
(i) no defective books ?
(ii) more than 0 but less than 4 defective books ?
(iii) more than 4 defective books ?
Solution:
Total number of books = 700
(i) P(no defective books) = \(\frac{400}{700}\) = \(\frac{4}{7}\)
(ii) P(more than 0 but less than 4 defective books) = \(\frac{269}{700}\)
13 (iii) P(more than 4 defective books) = \(\frac{13}{700}\)

Probability Class 9 Extra Questions Short Answer Type 1 and 2

Ch 15 Maths Class 9 Extra Questions Question 1.
Two coins are tossed simultaneously for 360 times. The number of times ‘2 Tails’ appeared was three times ‘No Tail’ appeared and number of times ‘1 Tail’ appeared is double the number of times ‘No Tail’ appeared. Find the probability of getting ‘Two tails’.
Solution:
Total number of outcomes = 360
Let the number of times ‘No Tail’ appeared be x
Then, number of times 2 Tails’ appeared = 3x
Number of times ‘1 Tail’ appeared = 2x
Now, x + 2x + 3x = 360
⇒ 6x = 360
⇒ x = 60
P(of getting two tails) = \(\frac{3 \times 60}{360}\) = \(\frac{1}{2}\)

Probability Class 9 Important Questions Question 2.
A die was rolled 100 times and the number of times, 6 came up was noted. If the experimental probability calculated from this information is \(\frac{2}{5}\), then how many times 6 came up ? Justify your answer.
Solution:
Here, total number of trials = 100
Let x be the number of times occuring 6.
We know, probability of an event
= \(\frac { Frequency\quad of\quad the\quad event\quad occuring }{ Total\quad number\quad of\quad trails }\)
⇒ \(\frac{x}{100}\) = \(\frac{2}{5}\) [∵ Probability is given)
⇒ x = 40

Probability Class 9 Extra Questions Long Answer Type

Probability Class 9 Extra Questions With Answers Question 1.
Three coins are tossed simultaneously 250 times. The distribution of various outcomes is listed below :
(i) Three tails : 30,
(ii) Two tails : 70,
(iii) One tail : 90,
(iv) No tail : 60
Find the respective probability of each event and check that the sum of all probabilities is 1.
Solution:
Here, the total number of chances = 250
Total number of three tails = 30

Probability Extra Questions For Class 9 Question 2.
A travel company has 100 drivers for driving buses to various tourist destination. Given
below is a table showing the resting time of the drivers after covering a certain distance (in km).

What is the probability that the driver was chosen at random :
(a) takes a halt after covering 80 km?
(b) takes a halt after covering 115 km?
(c) takes a halt after covering 155 km?
(d) takes a halt after crossing 200 km?
Solution:
Total number of drivers = 100
(a) P (takes a halt after covering 80 km) = \(\frac{13}{100}\)
(b) P (takes a halt after covering 115 km) = \(\frac{60}{100}\) = \(\frac{3}{5}\)
(c) P (takes a halt after covering 155 km) = \(\frac{90}{100}\) = \(\frac{9}{10}\)
(d) P (takes a halt after crossing 200 km) = \(\frac{10}{100}\) = \(\frac{1}{10}\)

Probability Class 9 Extra Questions With Solutions Question 3.
A company selected 2300 families at random and surveyed them to determine a relationship between income level and the number of vehicles in a home. The information gathered is listed in the table below :

If a family is chosen at random, find the probability that the family is :
(i) earning ₹7000 – ₹13000 per month and owning exactly 1 vehicle.
(ii) owning not more than one vehicle. (iii) earning more than ₹13000 and owning 2 or more than 2 vehicles. (iv) owning no vehicle
Solution:
Here, we have a total number of families = 2300
(i) Number of families earning ₹7000 to ₹13000 per month and owning exactly 1 vehicle = 295 + 525 = 820

Class 9 Maths Ch 15 Extra Questions Question 4.
A survey of 2000 people of different age groups was conducted to find out their preference
in watching different types of movies :
Type I + Family Type II → Comedy and Family
Type III → Romantic, Comedy, and Family 242.
Type IV → Action, Romantic, Comedy and Family

Find the probability that a person chosen at random is :
(a) in 18-29 years of age and likes type II movies
(b) above 50 years of age and likes all types of movies
(c) in 30-50 years and likes type I movies. :
Solution:
(a) Let E₁ be the event, between the age group (18 – 29) years and liking type II movies
Favourable outcomes to event E₁ = 160
∴ P(E₁) = \(\frac{160}{2000}\) = \(\frac{160}{2000}\)
(b) Let E₂ be the event, of age group above 50 years and like all types of movies
Favourable outcomes to event E₂ = 9
∴ P(E₂) = \(\frac{9}{2000}\)
(c) Let E₃ be the event, between age group (30 – 50) years and liking type I movies
Favourable outcomes to event E₃ = 505
∴ P(E₃) = \(\frac{505}{2000}\) = \(\frac{101}{400}\)

Probability Class 9 Extra Questions HOTS

Question 1.
In a kitchen, there are 108 utensils, consisting of bowls, plates, and glasses. The ratio of bowls, plates the glasses is 4:2:3. A utensil is picked at random. Find the probability that :
(i) it is a plate.
(ii) it is not a bowl.
Solution:
Total utensils in the kitchen = 108
Let number of bowls be 4x, number of plates be 2x and number of glasses be 3x
∴ 4x + 2x + 3x = 108
9x = 108
x = \(\frac{108}{9}\) = 12
Thus, number of bowls = 4 × 12 = 48
Number of plates = 2 × 12 = 24
Number of glasses = 3 × 12 =
(i)P (a plate) = \(\frac{24}{108}\) = \(\frac{2}{9}\)
(ii) P (not a bowl) = \(\frac{24+36}{108}\) = \(\frac{60}{108}\) = \(\frac{5}{9}\)

Question 2.
A bag contains 20 balls out of which x are white.
(a) If one ball is drawn at random, find the probability that it is white.
(b) If 10 more white balls are put in the bag, the probability of drawing a white ball will be double that in part (a), find x.
Solution:
Here, total no. of balls = 20
No. of white balls = x
∴ P(white ball) = \(\frac{x}{20}\)
Now, 10 more white balls are added
∴ Total no. of balls = 20 + 10 = 30
Total no. of white balls = x + 10
According to statement of question, we have
\(\frac{x+10}{30}\) = 2 × \(\frac{x}{20}\)
⇒ \(\frac{x+10}{3}\) = x
⇒ x + 10 = 3x
⇒ 2x = 10
⇒ x = 5

Question 3.
Here is an extract from a mortality table.

(i) Based on this information, what is the probability of a person aged 60′ of dying within a year ?
(ii) What is the probability that a person aged 61′ will live for 4 years ?
Solution:
(i) Clearly 16090 persons aged 60, (16090 – 11490), i.e., 4600 died before reaching their 61st birthday.
Therefore, P (a person aged 60 die within a year) = \(\frac{4600}{16090}\) = \(\frac{460}{1609}\)
(ii) Number of persons aged 61 years = 11490
Number of persons surviving for 4 years = 2320
P (a person aged 61 will live for 4 years) = \(\frac{2320}{11490}\) = \(\frac{232}{1149}\)

Probability Class 9 Extra Questions Value Based (VBQs)

Question 1.
An insurance company selected 2000 drivers at random (i.e., without any preference of one driver over another) in a particular city to find a relationship between age and accidents. The data obtained are given in the following table :

Find the probability of the following events for a driver-selected at random from the city :
(i) being 18 – 29 years of age and having exactly 3 accidents in one year.
(ii) being 30 – 50 years of age and having one or more accidents in a year.
(iii) having no accident in one year.
(iv) Which value would you like to remember from this data?
Solution:
Here, total number of drivers = 2000
(i) The number of drivers in the age group 18 – 29 having exactly 3 accidents = 70
So, P (driver in age group 18 – 29 having exactly 3 accidents in one year) = \(\frac{70}{2000}\) = 0.035
(ii). The number of drivers in the age group 30 – 50 and having one or more than one accidents in one year = 118 + 65 + 20 + 21 = 224
P (driver in age group 30 – 50 having one or more accidents in one year) = \(\frac{224}{2000}\) = 0.112
(iii) The number of drivers having no accident in one year = 395 + 520 + 390 = 1305
So, P (driver having no accident) = \(\frac{1305}{2000}\) = 0.6525
(iv) Most people in India died or injured due to accidents as compared to any other country. So, we should obey the traffic rules as life is very precious.

Question 2.
100 plants were sown in six different colonies A, B, C, D, E, and F. After 31 days, the number of plants survived as follows :

What is the probability of :
(i) more than 80 plants survived in a colony?
(ii) less than 82 plants survived in a colony?
(iii) which values are depicted from the above data?
Solution:
Here, we have total number of colonies = 6
(i) Number of colonies in which more than 80 plants survived = 4 (i.e., B, C, E and F)
∴ P(more than 80 plants survived in a colony) = \(\frac{4}{6}\) = \(\frac{2}{3}\)
(ii) Number of colonies in which less than 82 plants survived = 2 (i.e., A and D)
∴ P (less than 82 plants survived in a colony) = \(\frac{2}{6}\) = \(\frac{1}{3}\)
(iii) In order to keep environment safe, clean and green, we should grow more and more plants.