Category: CBSE Sample Papers

Students can access the CBSE Sample Papers for Class 12 Computer Science with Solutions and marking scheme Term 2 Set 4 will help students in understanding the difficulty level of the exam.

CBSE Sample Papers for Class 12 Computer Science Term 2 Set 4 with Solutions

Maximum Marks: 35
Time: 2 hours

Instructions:

• The question paper is divided into 3 sections – A, B and C.
• Section A, consists of 7 questions (1-7). Each question carries 2 marks.
• Section B, consists of 3 questions (8-10). Each question carries 3 marks.
• Section C, consists of 3 questions (11-13). Each question carries 4 marks.
• Internal choices have been given for question numbers 7, 8 and 12.

Section – A
(Each question carries 2 Marks)

Question 1.
Define the following terms with respect to stack
(i) Stack Top
Answer:
Stack Top The top of the stack is the last element of the stack, which is present at the top most position on the pile.

(ii) Stack Underflow
Answer:
Stack Underflow It happens in a delete operation. We can delete elements from a stack until it is empty, i.e. there is no element in it. Trying to delete an element from empty stack results in an exception called ‘underflow’.

Question 2.
(i) Expand the following
(a) WLAN
Answer:
WLAN → Wireless Local Area Network

(b) DNS
Answer:
DNS → Domain Name System

(ii) Name the three parts of optical fibre cable.
Answer:
Core, Cladding, Protective coating

Question 3.
Write the use of LIKE clause and a short explanation on the two characters used with it.
Answer:
This operator is used to search a specified pattern in a column. It is useful when you want to search rows to match a specific pattern or when you do not know the entire value.The SQL LIKE clause is used to compare a value to similar values using wildcard characters.

We describe patterns by using two special wildcard characters, given below

• The per cent sign (%) is used to match any substring.
• The underscore (_) is used to match any single character.

The symbols can also be used in combinations.

Question 4.
Consider the table Faculty whose columns’ name are F_ID, Name, Hiredate, Salary
Write the code using Python to insert the following record into the above table in MySQL. 101 RiyaSharma 12-10-2004 35000
Answer:

import mysql.connector
mycon = mysql .connector.connect
(host=“localhost”, user=“root”, passwd=‘‘system”, database=“Test”) cursor = mycon.cursor ( )
sql = “INSERT INTO FACULTY (F_ID, Name, Hiredate, Salary)
VALUES (%s, %‘s, %s, %s)”
val = [(101, “Riya Sharma”, “12-10-2004”, 35000)]
try:
cursor.executemany (sql, val)
mycon.commit ( ) except:
mycon.rol1 back ( )
mycon.close ( )

Question 5.
Write the output for SQL queries based on table CARDEN.
Table: CARDEN

(i) SELECT COUNT (DISTINCT Manufacturer) FROM CARDEN;
Answer:

(ii) SELECT COUNT (*) Manufacturer FROM CARDEN;
Answer:

(iii) SELECT CarName FROM CARDEN WHERE Capacity = 4;
Answer:

(iv) SELECT Code, Manufacturer FROM CARDEN WHERE Color = “White”;
Answer:

Question 6.
(i) Which command is used to select data from a database or view table information?
Answer:
SELECT

(ii) Give the syntax to insert a new row in a table.
Answer:
INSERT INTO table_name (Columnl, Column2, Column3, …)
VALUES. (Value1, Value2, Value3, …);

Question 7.
Consider the following table PAYMENTS
Table PAYMENTS

(i) Identify the degree and cardinality of the table.
(ii) Choose the suitable column which acts as primary key.
Or
(i) Identify the candidate key(s) from table PAYMENTS.
(ii) Which field will act as foreign key when another table DEPT has columns Department, DName.
Answer:
(i) Degree: 4
(ii) Empld Cardinality: 6
Or
(i) Empld, Emp_Name
(ii) Department

Section – B
(Each question carries 3 Marks)

Question 8.
Evaluate following postfix expression. Show the status of stack after execution of each operation.
3, 10, 4, +, *, 4, 3, *, –
Or
Sohan has a list containing 8 integers as marks of subject Science. You need to help him to create a program with separate user-defined function to perform the following operations based on the list.

• Push those marks into a stack which are greater than 75.
• Pop and display the content of the stack.

Simple Input
Marks = [75, 80, 56, 90, 45, 62, 76, 72]

Sample Output
80 90 76
Answer:
Given postfix expression is 3, 10, 4, +, *, 4, 3, *, –

Or

Marks = [75, 80, 56, 90, 45, 62, 76, 72]
def PUSH (St, Marks):
St. append(Marks)
def POP(St):
if St ! = [ ]:
return St. pop ( )
else;
return None
Stack1 = [ ]
for x in Marks:
if x > 75 :
PUSH (Stackl, x)
while True:
if Stack1! = [ ]:
print (POP(Stackl), end = " ")
else:
break

Question 9.
(i) A table PERSONS has following fields P_Id, FirstName, LastName, Address, City
Give the SQL command to display the FirstName that start with letter “T”.
Answer:
SELECT FirstName FROM PERSONS WHERE FirstName LIKE “T%”;

(ii) Rakesh wants to increase the price of some of the products by 20%, of his store whose price is less than 200. Assuming the following structure, what will be the query?

Answer:
UPDATE ITEM SET Price=Price + Price * 0.2 WHERE Price<200 ;
The UPDATE command updates data of a table. While updating, the expression for update value can be assigned to the updating field. The records to be updated can be specified as WHERE condition.

Question 10.
Sanjeev has created a database named LIBRARY in MySQL.
He now needs to create a table name BOOKS in the database to store the records of various books.

The table BOOKS has the following structure.
Table: BOOKS

Field Name	Datatype	Remark
Book_Id	Varchar (5)	Primary Key
Book_Name	Char (20)
Author_Name	Char (20)
Publishers	Char (20)
Price	Integer
Type	Char (10)
Qty	Integer

Help him to complete the task by suggesting SQL commands.
Answer:
CREATE DATABASE LIBRARY;
CREATE TABLE BOOKS
(Book_Id Varchar (5) Primary Key, Book_Name Char (20),
Author_Name Char (20),
Publishers Char (20),
Price Integer,
Type Char (10),
Qty Integer);

Section – C
(Each question carries A Marks)

Question 11.
Write queries (i) to (iv) based on the table Teacher and Posting given below
Table : Teacher

Table: Posting

P_ID	Department	Place
1	History	Agra
2	English	Raipur
3	Mathematics	Delhi
4	CQmputer Science	Meerut

(i) To list the names of female teachers who are in Mathematics department.
Answer:
SELECT Name FROM Teacher WHERE Department = “Mathematics” AND Gender= “F”;

(ii) To display teacher’s name, salary, age for male teachers only.
Answer:
SELECT Name, Salary, Age FROM Teacher WHERE Gender = “M”;

(iii) To display name, bonus for each teacher where bonus is 10% of salary.
Answer:
SELECT Name, Salary * 0.1 AS Bonus FROM Teacher;

(iv) To display Name, Department of teachers who are in Delhi.
Answer:
SELECT Name, Department FROM Teacher T, Posting P WHERE T. Department = P. Department AND PI ace = “Del hi”;

Question 12.
(i) Define in brief POP and SMTP protocols used for E-mail.
Or
What kind of communication channels is required for establishing the connection between TV channels?
Answer:
Post Office Protocol (POP) It is a
computer networking protocol used as Internet standard protocol. POP extracts and retrieves email from a remote mail server for access by the’host machine. It is an application layer protocol that provides end users an ability to fetch and receive email. The most recent version of POP protocol is used in POP3.
Simple Mail Transfer Protocol (SMTP) It is a set of commands that are required for sending and receiving of the email. The email sender uses SMTP to send an email to the mail server and further, mail server uses SMTP to forward that received mail to the receiver mail server.
Or
For establishing the connection between TV channels we require satellite communication. Satellites are an essential part of telecommunication systems. They carry a large amount of data in addition to TV signals. When the data is transmitted using satellite then it is said to be satellite communication. A satellite communication consists of an earth station and a satellite at a stationary orbit, which is about 22300 miles above the earth’s surface. A satellite communication is a space station that receives microwave signals from an earth-based station, amplifies the signals and broadcasts the signals back over a wide area to any number of earth-based stations.

(ii) What do you mean by an architecture of a network? Explain in brief Peer-to-Peer network.
Answer:

• Logical and structural layout of a network is called as network architecture, which consists of networking equipment, protocols and infrastructure. There are two types of network architecture – Peer-to-Peer and client server using different techniques.
• Peer-to-Peer (P2P) It is a connection between two nodes of the network. One sender can send message to exactly one receiver and vice-versa. Sending and receiving of data can be done using different channels or same channel turn by turn.

Question 13.
Tech Up Corporation (TUC) is a professional consultancy company. The company is planning to set up their new offices in India with its hub at Hyderabad. As a network adviser, you have to understand their requirement and suggest to them the best available solutions. Their queries are mentioned as (i) to (iv) below.

Block to block distances (in metre)

Block (From)	Block (To)	Distance
Human Resource	Conference	60
Human Resource	Finance	120
Conference	Finance	80

Expected number of computers to be installed in each block

Block	Computers
Human Resource	125
Finance	25
Conference	60

(i) What will the most appropriate block, where TUC should plan to install their server?
Answer:
TUC should install its server in Human Resource Block as it has maximum number of computers.

(ii) Draw a block to block cable layout to connect all the buildings in the most appropriate manner for efficient communication.
Answer:

The above layout is based on the minimum length of cable required, i.e. 140 m.

(iii) What will be the best possible connectivity out of the following, you will suggest to connect the new setup of offices in Bengalore with its London based office?
(a) Infrared
(b) Satellite link
(c) Ethernet cable
Answer:
(b) Satellite link

(iv) Company is planning to connect its Block in Hyderabad which is more than 20 km. Which type of network will be formed?
Answer:
MAN

Students can access the CBSE Sample Papers for Class 12 Computer Science with Solutions and marking scheme Term 2 Set 3 will help students in understanding the difficulty level of the exam.

CBSE Sample Papers for Class 12 Computer Science Term 2 Set 3 with Solutions

Maximum Marks: 35
Time: 2 hours

Instructions:

• The question paper is divided into 3 sections – A, B and C.
• Section A, consists of 7 questions (1-7). Each question carries 2 marks.
• Section B, consists of 3 questions (8-10). Each question carries 3 marks.
• Section C, consists of 3 questions (11-13). Each question carries 4 marks.
• Internal choices have been given for question numbers 7, 8 and 12.

Section – A
(Each question carries 2 Marks)

Question 1.
Why are data structures important? Give any two reasons.
Answer:

• Specific data structures are essential ingredients of many efficient algorithms and make possible the management of huge amounts of data, such as a large integrated collection of databases.
• Some programming languages emphasize on data structures rather than algorithms as the key organising factor in software design.

Question 2.
(i) Expand the following
(a) ARPANET
Answer:
ARPANET → Advanced Research Projects Agency Network

(b) ISP
Answer:
ISP → Internet Service Provider

(ii) Name the types of twisted pair cable.
Answer:
(a) Shielded Twisted Pair (STP) cable.
(b) Unshielded Twisted Pair (UTP) cable

Question 3.
Give the differences between primary key and foreign key in a table.
Answer:
Differences between primary key and foreign key are as follows:

Primary Key	Foreign Key
Primary key uniquely identifies a record in the table.	Foreign key is a field in the table that is primary key in another table.
It cannot have null values.	It can have null values.
Only one primary key is possible in a table.	More than one foreign keys are possible in a table.

Question 4.
Write the queries for the following questions using the table Product with the following fields
(P_ Code, P_Name, Qty, Price)
(i) Display the price of product having code as P06.
Answer:
SELECT Price FROM Product WHERE P_Code=“P06”;

(ii) Display the name of all products with quantity greater than 50 and price less than 500.
Answer:
SELECT P_Name FROM Product WHERE Qty>50 AND Price<500

Question 5.
Write the output of the queries (i) to (iv) based the table STUDENT,
Table : Student

(i) SELECT *FROM Student WHERE Grade = “A+”;
Answer:

(ii) SELECT RollNo, Marks FROM Student WHERE Name LIKE “R%”;
Answer:

(iii) SELECT MAX (Marks) FROM Student;
Answer:

(iv) SELECT Name FROM Student WHERE Marks > 80;
Answer:

Question 6.
(i) In SQL, which command is used to select only one copy of each set of duplicate rows?
Answer:
DISTINCT

(ii) Write the command to insert the row (18, Shaurya, 88, A) to the table Student whose fields are (RollNo, Name, Marks, Grade).
Answer:
INSERT INTO Student (RollNo,
Name, Marks, Grade)
VALUES (18, “Shaurya”, 88, “A”);

Question 7.
Consider the table Student given below
Table : Student

(i) Identify the degree and cardinality of a table.
(ii) Choose the field which can be used as primary key.
Or
(i) Identify the candidate key(s) of table Student.
(ii) Which command is used to show the content of table Student?
Answer:
(i) Degree: 4
Cardinality: 5
(ii) StudentId because it is identifying the record uniquely.
Or
(i) StudentId, FirstName, LastName
(ii) DESC Student;

Section – B
(Each question carries 3 Marks)

Question 8.
Anjali has a list containing 10 integers. You need to help her create a program with separate user defined functions to perform the following operations based on this list.

• Traverse the content of the list and push the numbers into the stack which are divided by 5.
• Pop and display the content of the stack

Sample input
L1 = [23, 45, 12, 75, 90, 17, 87, 42, 72, 65]
Sample output
45 75 90 65
Or
Write an algorithm to convert infix expression to postfix expression using stack.
Answer:

L1 = [23, 45, 12, 75, 90, 17, 87, 42, 72, 65]
def INPUT(S, L1):
S.append (L1)
def OUT(S):
if S! = [ ]:
return S.pop( )
else:
return None
Stack1 =[ ]
for i in L1:
if i% 5 = = 0:
INPUT(Stack1, i)
whi1e True:
if Stackl !=[]:
print(OUT(Stack1), end = “ ”)
else:
break

Or
Algorithm Steps:

• Step1: First of all enclose the EXP in parentheses, i.e. ( ).
• Step 2: Read next symbol of EXP and repeat steps 3 to 6 until the STACK is empty.
• Step 3: If the symbol read is operand then add it to PE.
• Step 4: If the symbol read is ’( ’ then Push it into STACK.
• Step 5: If the symbol read is operator then
  • Repeat while (Priority of TOP (STACK) > Priority of operator) Pop operator from STACK and add operator to PE.
  • Push operator into STACK.
• Step 6: If the symbol read is ‘)’ then
  • Repeat while (TOP (STACK)! = ‘ ( ’ )
    Pop operator from STACK
    Add operator to PE
  • Remove the ‘(’. [It must not be added to PE].
• Step 7: PE is the desired equivalent postfix expression.
• Step 8: Stop

Question 9.
(i) Write the statement to delete person named “Kari Pettersen” in the table PERSONS,
Answer:
DELETE FROM PERSONS
WHERE Name = “Kari Pettersen”;

(ii) Can we add any attribute in an existing table? If yes,
(a) Add SALARY attribute in a TEACHER table which already has TeacherlD and Tname as fields.
(b) After adding SALARY field add check constraint on SALARY that it should be at least 20000.
Answer:
Yes, we can add new attributes in an existing table. This can by using an ADD option with ALTER TABLE command. Add attribute salary in teacher table
(a) ALTER TABLE TEACHER ADD SALARY INT;
(b) ALTER TABLE TEACHER
ADD CHECK (SALARY>=20000);

Question 10.
Create a database FAME in MySQL. Also, create a table named FAMILY in the database to store the detail of family’s members. The table FAMILY has the following structure

Field Name	Data Type	Remark
Id	Integer (2)	Primary Key
Name	Char (20)	Not Null
FemaleMembers	Integer (2)
MaleMembers	Integer (2)
Income	Float (5)
Occupation	Char (20)

Answer:
CREATE DATABASE FAME;
CREATE TABLE FAMILY
(Id Integer (2) Primary Key,
Name Char (20) Not Null,
FemaleMembers Integer (2),
MaleMembers Integer (2),
Income FI oat (5),
Occupation Char (20));

Section – C
(Each question carries 4 Marks)

Question 11.
Study the following tables FLIGHTS and FARES and write SQL commands for the questions (i) to (iv).
Table: FLIGHTS

Table : FARES

(i) Display FL_NO and NO_FLIGHT from KANPUR to BENGALURU from the table FLIGHTS.
Answer:
SELECT FL_N0, N0_FLIGHT FROM
FLIGHTS WHERE STARTING = ‘KANPUR’ AND ENDING = ‘BENGALURU’;

(ii) Arrange the contents of the table FLIGHTS in the ascending order of FL_NO.
Answer:
SELECT * FROM FLIGHTS ORDER BY FL_N0;

(iii) Display the FL_NO and fare to be paid for the flights from DELHI to MUMBAI using the tables FLIGHTS and FARES, where the fare to be paid = FARE + FARE * TAX % 100.
Answer:
SELECT FL_N0, FARE + FARE * TAX%100 FROM FARES WHERE FL_N0 = (SELECT FL_No FROM FLIGHTS WHERE STARTING = ‘DELHI’ AND ENDING = ‘MUMBAI’ ) ;

(iv) Display the minimum fare INDIAN AIRLINES is offering from the table FARES.
Answer:
SELECT MIN( FARE) FROM FARES GROUP BY AIRLINES HAVING AIRLINES = ‘INDIAN AIRLINES’;

Question 12.
(i) Give any two needs of computer networking.
Or
What is WWW? Also, explain HTML and URI.
Answer:
Needs of computer networking are as
follows
(a) Resource Sharing Computer networking also allows the sharing of network resources, such as printers, scanners, dedicated servers, backup systems, input devices and Internet connections. By sharing resources, unique equipment like scanners, printers etc., can be made available to all network users simultaneously without being relocated, eliminating the need for expensive redundancies.

Data Protection and Redundancy Computer networking allows users to distribute copies of important information across multiple locations, ensuring essential information is not lost with the failure of any one computer in the network. By utilising central backup systems both on-site and off-site, unique documents and data can be gathered automatically from every computer in the network and securely backed up in case of physical computer damage or accidental deletion.
Or

• The World Wide Web (WWW) or Web in short, is an ocean of information, stored in the form of trillions of interlinked web pages and web resources.
• The resources on the web can be shared or accessed through the Internet.
• HTML HyperText Markup Language (HTML) is a language, which is used to design standardised web pages so that the web contents can be read and understood from any computer. Basic structure of every web page is designed using HTML.
• URI Uniform Resource Identifier (URI) is a unique address or path for each resource located on the web. It is also known as Uniform Resource Locator (URL). Every page on the web has a unique URL. For example, https://www.mhrd.gov.in, http:// www.ncert. nic.in, http://www.airindia.in, etc.

(ii) What do you mean by bandwidth and data transfer rate of a channel?
Answer:
In data communication, the transmission medium is also known as channel. The capacity of a channel is the maximum amount of signals or traffic that a channel can carry. It is measured in terms of bandwidth and data transfer rate as described below
Bandwidth Bandwidth of a channel is the range of frequencies available for transmission of data through that channel. Higher the bandwidth, higher the data transfer rate. Normally, bandwidth is the difference of maximum and minimum frequency contained in the composite signals. Bandwidth is measured in Hertz (Hz).

• 1 kHz =1000 Hz
• 1 MHz =1000 kHz = 1000000 Hz

Data Transfer Rate: Data travels in the form of signals over a channel. One signal carries one or more bits over the channel. Data transfer rate is the number of bits transmitted between source and destination in one second. It is also known as bit rate. It is measured in terms of bits per second (bps). The higher units for data transfer rates are

• 1 Kbps = 2¹⁰ bps=1024 bps
• 1 Mbps = 2²⁰ bps=1024 Kbps
• 1 Gbps = 2³⁰ bps=1024 Mbps
• 1 Tbps = 2⁴⁰ bps=1024 Gbps

Question 13.
China Middleton Fashion is planning to expand their network in India, starting with two cities in India of provide infrastructure for distribution of their product. The company has planned to set up their main office units in Chennai at the different locations and have named their offices as Production Unit, Finance Unit and Media Unit. The company has its Corporate Unit in Delhi. A rough layout of the same is as follows

The approximate distance between these units are as follows:

From	To	Distance
Production Unit	Finance Unit	70 m
Production Unit	Media Unit	15 km
Production Unit	Corporate Unit	2112 km
Finance Unit	Media Unit	15 km

In continuation of the above, the company experts have planned to install the following number of computers in each of their office units

Production Unit	150
Finance Unit	35
Media Unit	10
Corporate Unit	30

(i) Suggest the kind of network required (out of LAN, MAN, WAN) for connecting each of the following office units
(a) Production Unit and Media Unit.
(b) Production Unit and Finance Unit.
Answer:
(a) MAN
(b)LAN

(ii) Which one of the following device will you suggest for connecting all the . computers with in each of their office units?
(a) Switch/Hub
(b) Modem
(c) Telephone
Answer:
Switch/Hub

(iii) Suggest a cable/wiring layout for connecting the company’s local office units located in Chennai. Also, suggest an effective method/technology for connecting the company’s office unit located in Delhi.
Answer:

An effective method/technology for connecting the company’s office in Delhi and Chennai is broadband connection.

(iv) Suggest the most suitable place to install the server with reason.
Answer:
Production unit is suitable to install the server because it has maximum number of computers.

Students can access the CBSE Sample Papers for Class 12 Computer Science with Solutions and marking scheme Term 2 Set 5 will help students in understanding the difficulty level of the exam.

CBSE Sample Papers for Class 12 Computer Science Term 2 Set 5 with Solutions

Maximum Marks: 35
Time: 2 hours

Instructions:

• The question paper is divided into 3 sections – A, B and C.
• Section A, consists of 7 questions (1-7). Each question carries 2 marks.
• Section B, consists of 3 questions (8-10). Each question carries 3 marks.
• Section C, consists of 3 questions (11-13). Each question carries 4 marks.
• Internal choices have been given for question numbers 7, 8 and 12.

Section – A
(Each question carries 2 Marks)

Question 1.
Write steps of Push operation in stack.
Answer:
There are the following steps of Push operation
Step 1 Begin
Step 2 If (T0P==(MAX -1)) Then
Step 3 Print “Stack is full” goto step 6
Step 4 TOP = TOP +1
Step 5 DATA[TOP]=ITEM Step 6 End

Question 2.
(i) Expand the following
(a) FTP
(b) POP₃
Answer:
(a) FTP—File Transfer Protocol
(b) POP₃—Post Office Protocol version 3

(ii) In order to allow data transfer from server to only the intended computers, which network device is required in the lab to connect the computers?
Answer:
Switch

Question 3.
What is the difference between DBMS and RDBMS?
Answer:
Differences between DBMS and RDBMS are as follows

DBMS	RDBMS
In DBMS, relationship between two tables or files are maintained programmatically.	In RDBMS, relationship between two tables or files can be specified at the time of table creation,
DBMS does not support client- server architecture.	Most of the RDBMS  support client-server architecture.
DBMS does not support distributed databases.	Most of the RDBMS support distributed databases.
In DBMS, there is no security of data.	In RDBMS, there are multiple levels of security such as command level, object level.

Question 4.
Answer the following questions.
(i) Which method returns the next row from the result set as tuple?
Answer:
fetchone ()

(ii) If there are no more rows to retrieve, then what is returned?
Answer:
None

Question 5.
Write the output for queries (i) to (iv), which are based on tables TEACHER and COURSE.


(i) SELECT TeacherID, DOJ FROM TEACHER WHERE Salary BETWEEN 35000 AND 45000;
Answer:

(ii) SELECT DISTINCT TeacherlD FROM COURSE;
Answer:

(iii) SELECT TeacherlD, COUNT(*), MIN(Fee) FROM COURSE GROUP BY TeacherlD HAVING COUN(*)>1;
Answer:

(iv) SELECT COUNT(*), SUM(Fee) FROM COURSE;
Answer:

Question 6.
(i) Which command is used to remove the table definition and all data?
Answer:
DROP command

(ii) Which clause is similar to HAVING clause in MySQL?
Answer:
HAVING clause will act exactly same as WHERE clause, i.e. filtering the rows based on certain conditions.

Question 7.
Consider the table Store

On the basis of above table Store, answer the following questions.
(i) Can we define Item as a primary key or not?
(ii) Find the degree and cardinality of the table.
Or
(i) Identify the candidate key(s) from the table Store.
(ii) If there is another table Product whose fields are PId, ItemCode, Manufacturer
Which field will be considered as foreign key, if both tables are related in a database?
Answer:
(i) In the given table, we cannot define Item
as a primary key because there is a possibility of Item name duplication. The main condition for a key to be primary key is that its value cannot be duplicate, e.g. In Item, Sharpener and Eraser can be duplicate company wise.
(ii) Degree = 4
Cardinality =5
Or
(i) ItemCode, Item
(ii) ItemCode

Section – B
(Each question carries 3 Marks)

Question 8.
Abhinav has created a dictionary containing codes and designation as key value pairs of 5 employees. Write a program, with separate user defined functions to perform the following operations

• Insert the keys (designation of the employee into a stack where corresponding code is less than 110.
• Remove and display the content of the stack.
  Suppose, dictionary is

Dic={“Manager”:108, “Clerk” : 115, “Analyst”:112, “Operator”:105, “HR”:127}

Output

Manager

Operator

Or
A linear stack called Status contains the following information

• Phone number of Employee
• Name of Employee

Write the method to push an object containing Phone number of Employee and Name of Employee into the stack.
Answer:

Di c = { “Manager” : 108, "Clerk” : 115, “Analyst” : 112, "Operator” : 105, “HR” : 127}
def Insert(E,D):
E. append(D)
def Remove (E):
if E! = [ ]:
return E. pop! ) 
else:
return None 
Stack1 = [ ] 
for i in A: _
if A[i] < = 110: ’
Insert (Stackl, i) 
while True: 
if Stackl! = [ ]:
print (Remove!Stackl), end = “ ”) 
else: 
break
Or
def Push_element (Status, Top): 
phone_no = int( input!“Enter phone number : ”)) 
emp_name = input! “Enter empl oyee name : ”)
St = (phone_no, emp_name)
Status. append(St)
Top = Top + 1 
return Top

Question 9.
(i) Write a command to delete all the records from a table “Product”.
(ii) Gopi Krishna is using a table Employee. It has the following columns Code, Name, Salary, DeptCode
He wants to display maximum salary department wise. He wrote the following command

SELECT DeptCode, MAX(Salary) FROM Employee;

But he did not get the desired result.
Rewrite the above query with necessary changes to help him get the desired output.
Answer:
(i) DELETE FROM Product;
(ii) SELECT DeptCode, MAX(Salary)
FROM Employee GROUP BY DeptCode;

10.
Ayush has to create a database named School in MySQL. He now needs to create a table named Teacher in the database to store the records of various teachers. The table Teacher has the following structure

Help him to complete the task by suggesting appropriate SQL commands.
Answer:

CREATE DATABASE School ;
CREATE TABLE Teacher
(
T_No Varchar(3) Primary Key,
Name Char(30),
Salary Integer,
Address Varchar(50),
DOJ Date
);

Section-C
(Each question carries 4 Marks)

Question 11.
Consider the tables TEACHER and COURSE [From Q.No. (5)] and write the queries for (i) to (iv), which are based on given tables.
(i) Display TeacherlD, Tname and DOJ in descending order of Salary.
Answer:

SELECT TeacherlD, Tname, DOJ FROM
TEACHER ORDER BY Salary DESC;

(ii) Display Tname, DOJ, Cname, Startdate of all courses whose fee is less than or equal to 5000.
Answer:

SELECT Tname, DOJ, Cname, 
Startdate FROM TEACHER, Course 
WHERE TEACHER.TeacherID=Course. 
TeacherlD AND Course.Fee<=5000;

(iii) Display number of teachers’ city wise.
Answer:

SELECT City, COUNT(*) FROM 
TEACHER GROUP BY City;

(iv) Display all the teachers not working in Delhi or Dehradun.
Answer:

SELECT * FROM Teacher WHERE City' 
NOT IN (‘Delhi’, ‘Dehradun’);

Question 12.
(i) What is Wi-Fi communication? Explain in brief.
Or
Write the advantages and disadvantages of Wi-Fi.
Answer:
Wi-Fi stands for Wireless Fidelity, has a range of about 100 m and allows for faster rate between 10-54 Mbps. Wi-Fi services have been introduced for providing high speed Internet access at convenient public locations such as Airports, Universities etc. Wi-Fi is another name for wireless LAN or WLAN. Home and business networks (private and public hotspots) use it to connect computers and other wireless devices to each other with Internet.

Computers and other devices connect to a Wi-Fi network via a wireless router or access point. For Wi-Fi to work, we need a broadband Internet connection, a wireless router and a laptop or PC having wireless Internet card or external wireless adapter.

Or

Some advantages of Wi-Fi are as follows

• It can be used, while moving within the single range.
• Network can be created where you cannot lay cable network. It is a wireless connection that can merge together multiple devices.

Some disadvantages of Wi-Fi are as follows

• It is more costly than wired network.
• Radiation generated by Wi-Fi can effect human health.
• Power consumption is fairly high.

(ii) Which type of signals are received by the satellite space station from earth station?
Answer:
In a satellite communication, there is a space station that receives the microwave signals from an earth-based station. It amplifies the signals and then broadcasts signals back over a wide area to any number of earth-based stations.

Question 13.
The school in Delhi setting up a network between different wings of campus. There are 4 wings in the campus- Senior (S), Junior (J), Admin (A) and Hostel (H).

Distance between wings are as follows
A to S — 100 m
A to J — 200 m
A to H — 300 m
S to J — 400 m
S to H — 100 m
J to H — 350 m
Number of computers installed at each building
A — 20
S — 150
J — 40
H — 20
(i) Suggest any two best wired media to connect various buildings.
Answer:
Best wired media are optical fibre and Ethernet cable.

(ii) Give the name of most suitable building where server can be installed.
Answer:
Most suitable building is Senior wing to install a server because it has maximum number of computers.

(iii) Suggest any device or software which can be installed for providing security for whole network.
Answer:
Firewall can be placed with the server in senior building for providing the security for whole network.

(iv) Suggest any device and the protocol that will be needed to provide wireless Internet access to all devices phone or laptops in the campus.
Answer:
Device name Wi-Fi Router or Wireless
MODEM.
Protocol WAP or 802.11

Students can access the CBSE Sample Papers for Class 12 Accountancy with Solutions and marking scheme Term 2 Set 12 will help students in understanding the difficulty level of the exam.

CBSE Sample Papers for Class 12 Accountancy Standard Term 2 Set 12 for Practice

Time Allowed: 2 Hours
Maximum Marks: 40

General Instructions:

• This question paper comprises two Parts – A and B. There are 12 questions in the question paper. Alt 1 questions are compulsory.
• Part-A is compulsory for all candidates.
• Part-B has two options i.e., (i) Analysis of Financial Statements and (ii) Computerized Accounting. Students must attempt only one. of the given options.
• There is no overall choice. However, an internal choice has been provided in 3 questions of three marks and 1 question of five marks.

PART-A
(Accounting for Not-for-Profit Organisations, Partnership Firms and Companies)

Question 1.
Distinguish between Receipts and Payments Account and Income and Expenditure Account on the basis of:
(A) Posting of Items
(B) Period (2)

Question 2.
Khushi, Garima and Agrim were partners in a firm sharing profits in the ratio 4 : 3 : 3. The firm was dissolved on 31^st March, 2021. Pass the necessary Journal entries for the following transactions after various assets (other than cash and bank) and third party liabilities had been transferred to Realisation Account:

(A) The firm had stock of ₹ 1,60,000. Khushi took over 50% of the stock at a discount of 20% while the remaining stock was sold off at a profit of 30% on cost.

(B) Agrim’s Loan of ₹ 24,000 was settled at ₹ 25,000. (2)

Question 3.
Firoz, Shah and Qureshi were partners in a firm sharing profits in the ratio of 2 : 1 : 2. On 15^th February, 2021, Firoz died and the new profit sharing ratio between Shah and Qureshi was 4 : 11. On Firoz’s death the goodwill of the firm was valued at ₹ 1,80,000. Calculate gaining ratio and pass necessary journal entry for the treatment of goodwill on Firoz’s death without opening goodwill account. (2)

Question 4.
How are the following dealt with while preparing the final accounts of Kawaljeet Club for the year ended 31^st March, 2021:

Particulars	Amount ₹
Stock of stationery on 1st April, 2020	7,000
Stock of stationery on 31stMarch, 2021	3,000
Creditors for stationery on 1st April, 2020	4,000
Creditors for stationery on 31st March, 2021	8,000
Advance paid for stationery carried forward on 1st April, 2020	6,000
Advance paid for stationery on 31st March, 2021	1,500
Amount paid for stationery during the year 2020-21	42,000

OR
Show how are the following items dealt with while preparing the final accounts of Shaheer Cricket Club for the year ended 31^st March, 2021:
(i) Stadium Fund as at 31^stMarch, 2020 is ₹ 40,00,000, and Capital Fund as at 31st March, 2020 is ₹ 80,00,000.
(ii) Expenditure on construction of Stadium is ₹ 24,00,000. The construction work of stadium is in progress and has not yet completed.
(iii) Donation Received for Stadium on 1st January, 2021 is ₹ 20,00,000. (3)

Question 5.
Alpha, Beta, Gamma and Delta are partners in a firm sharing profits in the ratio of 3 : 3 : 2 : 2 respectively. On 31^st March, 2022 Delta retires from the firm and Alpha, Beta and Gamma decided to share the future profits in the ratio of 3 : 2 : 1. Goodwill of the firm is valued at ₹ 3,00,000. Goodwill already appears in the books of the firm at ₹ 2,25,000. The profits for the first year after Delta’s retirement amount to ₹ 6,00,000.
Give the necessary journal entries to record Goodwill and to distribute the profits. Show your calculations clearly. (3)

Question 6.
Kapoor Co. Limited issued 8,000,12% Debentures of ₹ 100 each on 1^st April, 2020 at a discount of 10% redeemable at a premium of 10% after five years.

Pass journal entries in the books of Kapoor Co. Limited for interest on debenture for the year ended 31^st March, 2021, assuming that the interest was payable half-yearly on 30th September and 31^st March. Tax is to be deducted @ 10%.
OR
Govinda Co. Limited obtained a loan of ₹ 10,00,000 from United Bank of India @ 12% p.a. interest. The company issued ₹ 15,00,000,12% Debentures of ₹ 100 each in favour of United Bank of India as Collateral Security. Pass necessary Journal entries for the above transactions:
(i) When company decided not to record the issue of 12% Debentures as Collateral Security.
(ii) When company decided to record the issue of 12% Debentures as Collateral Security. (3)

Question 7.
P, Q and R were partners in a firm sharing profits and losses in the ratio of 5 : 3 : 2. On 31^st March, 2021 their Balance Sheet was as follows:

R died on 31^st July, 2021. It was agreed that:

(i) Goodwill be valued at two and a half years’ purchase of the average profits of the last four years, which were as follows:
Years – Profit (₹)
2017 – 18 – 32,500
2018 – 19 – 30,000
2019 – 20 – 40,000
2020 – 21 – 37,500

(ii) Plant and Machinery be valued at ₹ 70,000; Patents and Trademarks at ₹ 20,000 and Building at ₹ 62,500.

(iii) For the purpose of calculation R’s share of profits in the year of his death, the profits in 2021-22 should be taken to have been accrued on the same scale as in 2020-21.

(iv) A sum of ₹ 17,500 was paid immediately to the executors of R and the balance was paid in four half yearly instalments together with interest at 12% p.a. starting from 31^st January, 2022.

Pass necessary journal entries to record the above transactions and prepare R’s Executors’ Account till the payment of instalments due on 31^st January, 2022.
OR
Pass necessary journal entries on the dissolution of a partnership firm in the following cases:
(A) Dissolution expenses ₹ 2,200 were paid by Sudha, a partner.

(B) Nakul, a partner agreed to do the work of dissolution for a commission of ₹ 4,000. He also agreed to bear the dissolution expenses. Actual dissolution expenses ₹ 4,200 were paid by Nakul.

(C) Taranjeet, a partner was appointed to look after the dissolution work for a remuneration of ₹ 20,000. He also agreed to bear the dissolution expenses. Actual dissolution expenses ₹? 19,600 were paid from the firm’s bank account.

(D) Sugandha, a partner was appointed to look after the dissolution work for a remuneration of ₹ 30,000. She also agreed to bear the dissolution expenses. Actual dissolution expenses ₹ 26,000 were paid by partner ‘Subhash’ on behalf of Sugandha.

(E) Malvika, a partner was appointed to look after the process of dissolution for a remuneration of ₹ 18,000. She also agreed to pay the dissolution expenses. Malvika took away Motor Car of ₹ 18,000 as her remuneration. Motor Car had already been transferred to the Realisation Account. (5)

Question 8.
Ajmeria Limited was incorporated on 1^st April, 2014 with registered office in Rajasthan. The company is growing year by year, and begins to expand its operations throughout India. To expand their business in Madhya Pradesh, directors of the company decided to take over one of the well-known firm of Madhya Pradesh, Pandaya Limited,
On 1^st April, 2021 Ajmeria Limited bought the business of Pandaya Limited consisting sundry assets of ₹ 72,00,000 and sundry liabilities of ₹ 20,00,000 for a consideration of ₹ 61,44,000.

Ajmeria Limited issued 12% Debentures of ₹ 100 each fully paid, at a discount of 4% in satisfaction of purchase consideration to Pandaya Limited. On 10^th June, 2021, the company also issued 1,000, 12% Debentures of ₹ 100 each credited as fully paid-up to the promoters for their services to incorporate the company.
You are required to answer the following questions:
(A) Calculate the amount of Goodwill purchased by Ajmeria Limited of Pandaya Limited.
(B) Pass journal entry for the purchase of business of Pandaya Limited.
(C) Pass journal entry for the allotment of debentures to Pandaya Limited.
(D) Pass journal entry for the allotment of debentures to the promoters.
(E) Calculate the amount of annual fixed obligation associated with debentures. (5)

Question 9.
Receipts and Payments Account of Rawalpindi Sports Club for the year ending 31^st March, 2021 is as follows:


Additional Information:
(i) Subscriptions outstanding was ₹ 1,200 on March 31, 2020 and ₹ 3,200 on March 31, 2021.
(ii) Locker rent outstanding on March 31, 2021 was ₹ 250.
(iii) Salary outstanding on March 31, 2021 was ₹ 1,000.
(iv) Fixed Deposit was made on 1^st January, 2021 @10% p.a.
(v) On April 1, 2020, club has following assets: Building ? 36,000, Furniture ^ 12,000, and Sports Equipments ₹ 17,500. Depreciation on these items is to be charged at 10% (including purchase).
(vi) Income and Expenditure Account for the year ending 31^st March, 2021 shows a surplus of ₹ 26,300.
From the Receipts and Payments Account and additional information provided, you are required to prepare Balance Sheet of Rawalpindi Sports Club as on 31st March, 2021. (5)

PART-B
Option-1
(Analysis of Financial Statements)

Question 10.
State whether the following transactions will result in inflow, outflow or no flow of cash while preparing Cash Flow Statement:
(A) Interest received on debentures ₹ 12,000.
(B) Increase in Inventories by ₹ 45,000. (2)

Question 11.
From the following Statement of Profit and Loss of Romita Limited as at 31 March, 2021, prepare Comparative Statement of Profit and Loss:

OR
From the following information provided of Vineeta Limited, for the year ended 31st March, 2020 and 2021, prepare a Common Size Statement of Profit and Loss:

Particulars	2020-21	2019-20
Revenue from Operations	₹ 50,00,000	₹ 40,00,000
Other Income	₹ 15,00,000	₹ 7,50,000
Employee Benefit Expenses	₹ 20,00,000	₹ 14,00,000
Depreciation and Amortisation Expenses	₹ 60,000	₹ 30,000
Administrative and General Expenses	₹ 50,000	₹ 45,000
Other Expenses	₹ 4,00,000	₹ 6,00,000
Tax Rate	40%	40%

Question 12.
From the following Balance Sheet of Jionee Limited and the additional information as on 31^st March, 2022, prepare a Cash Flow Statement:

Notes to Accounts:


Additional Information:
(i) ₹ 50,000, 12% Debentures were issued on 31^st March, 2022.
(ii) During the year, a piece of machinery costing ₹ 40,000, on which accumulated depreciation
was ₹ 20,000, was sold at a loss of ₹ 5,000. (5)

Students can access the CBSE Sample Papers for Class 12 Economics with Solutions and marking scheme Term 2 Set 11 will help students in understanding the difficulty level of the exam.

CBSE Sample Papers for Class 12 Economics Term 2 Set 11 for Practice

Time allowed: 2 Hours
Maximum Marks: 40

General Instructions:

• This is a Subjective Question Paper containing 13 questions.
• This paper contains 5 questions of 2 marks each, 5 questions of 3 marks each and 3 questions of 5 marks each.
• 2 marks questions are Short Answer Type Questions and are to be answered in 30-50 words.
• 3 marks questions are Short Answer Type Questions and are to be answered in 50-80 words.
• 5 marks questions are Long Answer Type Questions and are to be answered in 80-120 words.
• This question paper contains Case/Source Based Questions.

Question 1.
Ex-post investment means fixed capital with production units during a particular period of time. Defend or refute the statement with valid reason.
OR
Marginal propensity to consume represents the slope of the consumption function. Defend or refute the statement with valid reason. (2)

Question 2.
In an economy, 20 percent of increased income is saved. How much will be the increase in income if investment increases by ₹10,000? Calculate.
OR
Estimate the change in final income if Marginal Propensity to Consume (MPC) is 0.75 and change in initial investment is ₹2,000 crores. (2)

Question 3.
Discuss briefly, the concept of ‘informalisation of workforce’, in the context of Indian economy. (2)

Question 4.
“Sustainable development is the only way that will allow economy to have a proper development.” Justify the statement.
OR
“Infrastructure is the support system on which depends the modern agriculture depends.” Justify the statement. (2)

Question 5.
Analyze the following information in reference to India and compare with other countries on the grounds of ‘Government health spending as a % of GDP’.

Question 6.
How will you treat the foLLowing whiLe estimating domestic product of a country?
Give reasons for your answer :
(A) Profits earned by branches of country’s bank in other countries.
(B) Gifts given by an employer to his employees on independence day.
(C) Purchase of goods by foreign tourists.
OR
If the Real Gross Domestic Product is f 400 and Price Index (base=100) is 120, calculate the Nominal Gross Domestic Product. 3

Question 7.
On the basis of below information, compare and contrast India and China’s sectoral contribution towards GVA/GDP. What does it indicate? (3)

Sector	Contribution to GVS
	India	China
Agriculture	16	7
Industry	30	41
Services	54	52
Total	100	100

Read the following case carefully and answer question number 8 and 9 given below:

India’s ambition of sustaining its relatively high growth depends on one important factor: infrastructure. The country, however, is plagued with a weak infrastructure incapable of meeting the needs of a growing economy and growing population. S&P Global Ratings projects India’s GDP to grow around 8% for the next three fiscal years, among the fastest in large, growing economies. The government also aims to significantly boost the manufacturing sector to contribute an all-time high of about 25% of GDP by 2025, from below 16% currently.

India is striving to improve its manufacturing competitiveness at a time when manufacturing powerhouse China is shifting toward consumption-led growth. China now faces the risk of overcapacity in segments such as port and power. For India, on the other hand, its road to sustainably higher growth and a competitive manufacturing sector goes through robust and reliable national infrastructure, especially in power and transportation.

Question 8.
State and explain the type of infrastructure stated in the above text. (3)

Question 9.
“India is incapable of meeting the needs of a growing economy and growing population.” Explain. (3)

Question 10.
As the examples of India, China and Pakistan show; countries are trying various means to strengthen their own domestic economies. What are the various means by which countries are trying to do so? (3)

Question 11.
Calculate national income from the following data:
(i) Personal Tax 80
(ii) Private final consumption expenditure 600
(iii) Undistributed profits 30
(iv) Private income 650
(v) Government final consumption expenditure 100
(Vi) Corporate tax 50
(vi) Net domestic fixed capital formation 70
(viii) Net indirect tax 60
Ox) Depreciation 14
(x) Change in stocks (-)10
(xi) Net imports 20
(xii) Net factor income to abroad 10
OR
Suppose the Gross Domestic Product (GDP) of Nation X was ₹2,000 crores in 2018 – 19, whereas the Gross Domestic Product of Nation Y in the same year was ₹120,000 crores. If the Gross Domestic Product of Nation X rises to ₹4,000 crores in 2019 – 20 and the Gross Domestic Product of Nation Y rises to ₹200,000 crores in 2019 – 20. Compare the rate of change of GDP of Nations X and Y, taking 2018 – 19 as base year. (5)

Question 12.
(A) Giving reason, state whether following the statement is true or false.
A car covering a distance of 300 km in 5 hours includes both stock as well as flow variable.
(B) ‘Subsidies to the producers, should be treated as transfer payments.’ Defend or refute the given statement with valid reason. (5)

Question 13.
“India’s GDP contracted 23.9% in the April- June quarter of 2020-21 as compared to same period of 2019-20, suggesting that the lockdown has hit the economy hard”.

State and discuss any two fiscal measures that may be taken by the Government of India to correct the situation indicated in the above news report. (5)

Students can access the CBSE Sample Papers for Class 12 Computer Science with Solutions and marking scheme Term 2 Set 2 will help students in understanding the difficulty level of the exam.

CBSE Sample Papers for Class 12 Computer Science Term 2 Set 2 with Solutions

Maximum Marks: 35
Time: 2 hours

Instructions:

• The question paper is divided into 3 sections – A, B and C.
• Section A, consists of 7 questions (1-7). Each question carries 2 marks.
• Section B, consists of 3 questions (8-10). Each question carries 3 marks.
• Section C, consists of 3 questions (11-13). Each question carries 4 marks.
• Internal choices have been given for question numbers 7, 8 and 12.

Section – A
(Each question carries 2 Marks)

Question 1.
Write some applications of stack in real life.
Answer:
Some applications of stack in real life are

• Pile of clothes in an almirah.
• Multiple chairs in a vertical pile.
• Bangles worn on wrist.
• Pile of boxes of eatables in pantry or on a kitchen shelf.

Question 2.
(i) Expand the following
(a) DTR
(b) NIC
Answer:
(a) DTR → Data Transfer Rate
(b) NIC → Network Interface Card

(ii) Give some examples of guided media.
Answer:
Examples of guided media are Ethernet cable or Twisted pair cable, Co-axial cable and Optical fibre cable.

Question 3.
What do you mean by Database Management System?
Answer:
A Database Management System (DBMS) or database system in short, is a software that can be used to create and manage databases. DBMS lets users to create a database, store, manage, update/modify and retrieve data from that database by users or application programs.

Some examples of open source and commercial DBMS include MySQL, Oracle, PostgreSQL, SQL Server, Microsoft Access, MongoDB.

Question 4.
A resultset is extracted from the database using the cursor object (that has been already created) by giving the following statement

Result = cursor.fetchmany ([size])

(i) How many records will be returned by fetchmany() method?
Answer:
It returns number of rows specified by the size argument.

(ii) What will be the datatype of Result object after the given command is executed?
Answer:
list of tuples.

Question 5.
Give the output of the following SQL statements based on table APPLICANTS. . Table : APPLICANTS

(i) SELECT NAME, JOINYEAR FROM APPLICANTS WHERE GENDER = ‘F’ AND C_ID = ‘A02’;
Answer:

(ii) SELECT MIN(JOINYEAR) FROM APPLICANTS WHERE GENDER = ‘M’ ;
Answer:

(iii) SELECT A VG ( FEE) FROM APPLICANTS WHERE C_ID=‘A01′ OR C_ID=‘A05’;
Answer:

(iv) SELECT Name, Fee FROM APPLICANTS WHERE Name LIKE “E%”;
Answer:

Question 6.
(i) Write the SQL query to list all tables in database.
Answer:
SHOW TABLES;

(ii) Write the SQL query to create a table STUDENT with roll no and student’s name (sname).
Answer:
CREATE TABLE STUDENT (roll no int, sname char (20));

Question 7.
Consider the table ITEM given below.
im – 2
(i) Identify the primary key of table ITEM. Also, justify your answer.
(ii) Identify degree and cardinality of the table.
Or
(i) Identify the candidate key(s) from the table ITEM.
(ii) Which statement is used to add a column Quantity in table ITEM?
Answer:
(i) ItemNo should be made the primary key as it uniquely identifies each record of the table,
(ii) Degree: 4
Cardinality: 4
Or
(i) ItemNo, Name
(ii) ALTER TABLE ITEM ADD Quantity Integer (5);

Section – B
(Each question carries 3 Marks)

Question 8.
A linear stack called result contains the following information
(i) Code of Item
(ii)Name of Item
(iii) Price of particular item
Write the method PUSH () to push an object containing Code, Name and Price of Item into the stack.
Or Write the steps to create the stack of glasses.
Answer:

def PUSH (result. Top):
Code = int ( input ("Enter the code of item:”))
Name = input (“Enter the name of item:”)
Price = int(input("Enter the price of item:"))
St = (Code, Name, Price) 
result.append(St)
Top = Top + 1 
return Top

Or

The stack is a linear and ordered collection of elements. The simple way to implement a stack in Python is using the data type list. We can fix either of the sides of the list as TOP to insert/remove elements. We can use built-in methods append () for push() and pop() of the list for implementation of the stack.

As these built-in methods insert/delete elements at the rightmost end of the list, hence explicit declaration of TOP is not needed. Following steps can be used to make stack of glasses
Step 1 Insert/delete elements (glasses).
Step 2 Check if the STACK is empty (no glasses in the stack).
Step 3 Find the number of elements (glasses) in the STACK.
Step 4 Read the value of the topmost element (number on the topmost glass) in the STACK.

Question 9.
(i) Write the syntax to perform inner join in two tables.
Answer:

SELECT coll, col 2
FROM tablet INNER JOIN table2 
ON tablel.column_name = 
table2.column_name;

(ii) Categorize the following commands into DCL and DDL commands
REVOKE, ALTER, DROP, GRANT, RENAME
Answer:
DCL commands REVOKE, GRANT
DDL commands ALTER, DROP,
RENAME

Question 10.
Write the code to create a database RECORD and also create a table RECIPIENT into a database RECORD. The fields of table are as follows

Answer:

CREATE DATABASE RECORD;
CREATE TABLE RECIPIENT 
(Redd varchar(5) Primary Key,
RecName char(20) Not Null,
RecAddress char(30),
RecCity char(20),
Gender char(2));

Section – C
(Each question carries A Marks)

Question 11.
Write the SQL commands for (i) to (iv) on the basis of the table HOSPITAL.

(i) To show all information about the patients of Cardiology Department.
Answer:

SELECT * FROM HOSPITAL WHERE
Department = ‘Cardiology’;

(ii) To list the name of female patients, who are in Orthopaedic Department.
Answer:

SELECT Name FROM HOSPITAL WHERE 
Department = ‘Orthopaedic’ AND 
Sex = ‘F’;

(iii) To list names of all patients with their date of admission in ascending order.
Answer:

SELECT Name FROM HOSPITAL ORDER 
BY Dateofadm;

(iv) To display name of doctor are older than 30 years and charges for consultation fee is more than 500.
Answer:

SELECT NAME FROM HOSPITAL WHERE 
Age>30 AND Charges>500;

Question 12.
(i) What is the use of following devices?
(a) Modem
(b) Hub
Or
Explain star topology and bus topology.
(ii) List the components of data communication and explain any two of them in brief.
Answer:
(i) (a) Modem Modem stands for’MOdulator DEModulator’. It refers to a device used for conversion between analog signals and digital signals. We know computers store and process data in terms of Os and Is. However, to transmit data from a sender to a receiver, or while browsing the Internet, digital data are converted to an analog signal and the medium (be it free-space or a physical media) carries the signal to the receiver. There are modems connected to both the source and destination nodes. The modem at the sender’s end acts as a modulator that converts the digital data into analog signals. The modem at the receiver’s end acts as a demodulator that converts the analog signals into digital data for the destination node to understand.

(b) Hub An ethemet hub is a network device used to connect different devices through wires. Data arriving on any of the lines are sent out on all the others. The limitation of hub is that if data from two devices come at the same time, they will collide.

Or

Star Topology In star topology, each communicating device is connected to a central node, which is a networking device like a hub or a switch.

Star topology is considered very effective, efficient and fast as each device is directly connected with the central device. Although, disturbance in one device will not affect the rest of the network, any failure in a central networking device may lead to the failure of complete network.

Bus Topology In bus topology, each communicating device connects to a transmission medium, known as bus. Data sent from a node are passed on to the bus and hence are transmitted to the length of the bus in both directions.

That means, data can be received by any of the nodes connected to the bus. In this topology, a single backbone wire called bus is shared among the nodes, which makes it cheaper and easier to maintain. Both ring and bus topologies are considered to be less secure and less reliable.

(ii) There are five components required for data communication

1. Sender
2. Receiver
3. Message
4. Communication channel
5. Protocols

Sender A sender is a computer or any such device which is capable of sending data over a network. It can be any computer, mobile phone, smart watch, walkie-talkie, video recording device, etc.

Receiver A receiver is a computer or any such device which is capable of receiving data from the network. It can be any computer, printer, laptop, mobile phone, television, etc. In computer communication, the sender and receiver are known as nodes in a network.

Question 13.
Workalot consultants are setting up a secured network for their office campus of Gurgaon for their day-to-day office and web based activities. They are planning to have connectivity between 3 buildings and the head office situated in Mumbai.

Answer the questions (i) to (iv) after going through the building positions in the campus and other details, which are given below

(i) Suggest the most suitable place (i.e. building) to house the server of this organisation. Also, give a reason to justify your suggested location.
Answer:
Building RED is the suitable place to house the server because it has maximum number of computers.

(ii) Suggest a cable layout of connections between the buildings inside the campus.
Answer:

(iii) Suggest the placement of the following devices with justification
(a) Switch
(b) Repeater
Answer:
(a) Switches are needed in every building as they help share bandwidth in every building.
(b) Repeaters may be skipped as per above layout (because distance is less than 100 m), however if building GREEN and building RED are directly connected, we can place a repeater there as the distance between these two buildings is more than 100 m.

(iv) The organisation is planning to provide a high speed link with its head office situated in the Mumbai using a wired connection. Which of the following cables will be most suitable for this job?
(a) Optical fibre
(b) Co-axial cable
(c) Ethernet cable
Answer:
(b) Co-axial cable

Students can access the CBSE Sample Papers for Class 12 Computer Science with Solutions and marking scheme Term 2 Set 1 will help students in understanding the difficulty level of the exam.

CBSE Sample Papers for Class 12 Computer Science Term 2 Set 1 with Solutions

Maximum Marks: 35
Time: 2 hours

Instructions:

• The question paper is divided into 3 sections – A, B and C.
• Section A, consists of 7 questions (1-7). Each question carries 2 marks.
• Section B, consists of 3 questions (8-10). Each question carries 3 marks.
• Section C, consists of 3 questions (11-13). Each question carries 4 marks.
• Internal choices have been given for question numbers 7, 8 and 12.

Section – A
(Each question carries 2 Marks)

Question 1.
Give any two characteristics of stacks.
Answer:
A stack is an abstract data type that holds an ordered, linear sequence of items. The characteristics of stack are

1. It is a Last In First Out (LIFO) data structure which means the item which is inserted last in the stack will be the first one to delete from the Stack.
2. The insertion and deletion happens at one end i.e. from the top of the stack.

Question 2.
(i) Expand the following
(a) SMTP
Answer:

• SMTP stands for Simple Mail Transfer
• Protocol. It is an internet standard communication protocol for electronic mail transmission.

(b) XML
Answer:
XML stands for extensible Markup Language. It consists of a set of codes, or tags, that describe the text in a digital document where the tags are not predefined.

(ii) Out of the following, which is the fastest wired and wireless medium of transmission? Infrared, Coaxial cable, Optical fibre, Microwave, Ethernet cable
Answer:

• Wired → Optical fibre
• Wireless → Microwave

Question 3.
Differentiate between char(n) and varchar(n) data types with respect to databases.
Answer:

char(n)	varchar(n)
It stores a fixed length string between 1 and 255 characters.	It stores a variable length string.
If the value is of smaller length, then it adds blank spaces.	length.
Some space is wasted in it.	in varchar(n).

Question 4.
A resultset is extracted from the database using the cursor object (that has been already created) by giving the following statement.

Mydata = cursor.fetchone()

(i) How many records will be returned by fetchone() method?
Answer:
fetchone() method retrieves the next row of a query result set and returns a single sequence, or none if no more rows are available.So one record will be returned by fetchone() method.

(ii) What will be the datatype of Mydata object after the given command is executed?
Answer:
tuple is the datatype of Mydata object after the given command is executed. Tuples are used to store heterogeneous elements, which are elements belonging to different data types.

Question 5.
Write the output of the queries (i) to (iv) based on the table FURNITURE given below.
Table : FURNITURE

(i) SELECT SUM(DISCOUNT) FROM FURNITURE WHERE C0ST>15000;
Answer:

(ii) SELECT MAX(DATEOFPURCHASE) FROM FURNITURE;
Answer:

(iii) SELECT * FROM FURNITURE WHERE DISCOUNTS AND FID LIKE “T%”;
Answer:

(iv) SELECT DATEOFPURCHASE FROM FURNITURE WHERE NAME IN (“Dinning Table”, “Console Table”);
Answer:

Question 6.
(i) Which command is used to view the list of tables in a database?
Answer:
SHOW TABLES, command is used to view the list of tables in a database.

(ii) Give one point of difference between an equi-join and a natural join.
Answer:
Differences between equi-join and a natural join are as follows:

equi-join	natural join
The join in which columns from two tables are compared for equality.	The join in which only one of the identical columns existing in both tables is present.
Duplicate columns are shown.	No duplication of columns.

Question 7.
Consider the table MOVIEDETAILS given below
Table: MOVIEDETAILS

(i) Identify the degree and cardinality of the table.
(ii) Which field should be made the primary key? Justify your answer.
Or
(i) Identify the candidate key(s) from the table MOVIEDETAILS.
(ii) Consider the table SCHEDULE given below.
Table: SCHEDULE

SLOTID	MOVIEID	TIMESLOT
S001	M010	10 AM to 12 PM
S002	M020	2 PM to 5 PM
S003	M010	6 PM to 8 PM
S004	M011	9 PM to 11 PM

Which field will be considered as the foreign key if the tables MOVIEDETAILS and SCHEDULE are related in a database?
Answer:
(i) Degree is the number of attributes or columns present in a table, So Degree is 5. Cardinality is the number of tuples or rows present in a table. So, Cardinality is 6.

(ii) MOVIEID should be made the primary key as it uniquely identifies each record of the table.
Or
(i) Candidate key in SQL is a set of attributes that uniquely identify tuples in a table. The Primary key should be selected from the candidate keys. Every table must have at least a single candidate key. So, MOVIEID and TITLE are the candidate keys in table MOVIEDETAILS.

(ii) A foreign key is a column or combination of columns that is used to establish and enforce a link between the data in two tables to control the data that can be stored in the foreign key table. So MOVIEID is the foreign key if the tables MOVIEDETAILS and SCHEDULE are related in a database.

Section – B
(Each question carries 3 Marks)

Question 8.
Julie has created a dictionary containing names and marks as key value pairs of 6 students. Write a program, with separate user defined functions to perform the following operations

• Push the keys (name of the student) of the dictionary into a stack, where the corresponding value (marks) is greater than 75.
• Pop and display the content of the stack.

For example If the sample content of the dictionary is as follows
R={“OM”:76/ “JAr’:45, “BOB”:89, “ALI”:65, “ANU”:90, “TOM”:82}
The output from the program should be
TOM ANU BOB OM
Or
Alam has a list containing 10 integers. You need to help him create a program with separate user-defined functions to perform the given operations based on this list.

• Traverse the content of the list and push the even numbers into a stack.
• Pop and display the content of the stack.

For example, If the sample content of the list is as follows
N=[12,13, 34, 56, 21, 79, 98, 22, 35, 38]
Sample Output of the code should be:
38 22 98 56 34 12
Answer:

R={" 0M": 76 , "JAI":45, "B0B":89, ”ALI": 65 , "ANU":90 , "T0M":82) def PUSH(S,N):
S.append(N)
def POP(S):
if S!=[]:
return S.pop()
else:
return None
ST=[ ]
for k in R:
if R[k]>=75:
PUSH(ST, k)
while True:
if ST!=[]:
print(POP(ST),end=" ")
else:
break

Or

N=[12, 13, 34, 56, 21, 79, 98, 22, 35, 38]
def PUSH(S, N):
S.append(N)
def POP(S):
if S!=[]:
return S.pop()
else:
return None
ST=[ ]
for k in N:
if k%2==0:
PUSH(ST, k)
while True:
if ST!=[ ]:
print(P0P(ST),end=" ”)
else:
break

Question 9.
(i) A table, ITEM has been created in a database with the following fields
ITEMCODE, ITEMNAME, QTY, PRICE
Give the SQL command to add a new field, DISCOUNT (of type Integer) to the ITEM table.
Answer:

ALTER TABLE ITEM ADD Discount INT;

(ii) Categorize following commands into DDL and DML commands?
INSERT INTO, DROP TABLE, ALTER TABLE, UPDATE…SET
Answer:
DDL means ‘Data Definition Language’. It is used to create and modify the structure of database objects in SQL. So, DDL commands are DROP TABLE, ALTER TABLE. *
DML is ‘Data Manipulation Language’ which is used to manipulate data itself.
So, DML commands are INSERT INTO, UPDATE…SET.

Question 10.
Charu has to create a database named MYEARTH in MySQL.
She now needs to create a table named CITY in the database to store the records of various cities across the globe. The table CITY has the following structure.
Table : CITY

Field Name	Data Type	Remarks
CITYCODE	CHAR(5)	Primary Key
CITYNAME	CHAR(30)
SIZE	INTEGER
AVGTEMP	INTEGER
POPULATIONRATE	INTEGER
POPULATION	INTEGER

Help her to complete the task by suggesting appropriate SQL commands.
Answer:
Command to create database
CREATE DATABASE MYEARTH;

Command to create table

CREATE TABLE CITY(
CITYCODE CHAR(5) PRIMARY KEY,
CITYNAME CHAR(30),
SIZE INT,
AVGTEMP INT,
POPULATIONRATE INT,
POPULATION INT,
);

Section – C
(Each question carries 4 Marks)

Question 11.
Write queries (i) to (iv) based on the tables EMPLOYEE and DEPARTMENT given below
Table : EMPLOYEE

Table: DEPARTMENT

DEPTID	DEPTNAME	FLOORNO
D001	Personal	4
D002	Admin	10
D003	Production	1
D004	Sales	3

(i) To display the average salary of all employees, department wise.
Answer:
SELECT AVG(SALARY)
FROM EMPLOYEE ,
GROUP BY DEPTID;

(ii) To display name and respective department name of each employee whose salary is more than 50000.
Answer:
SELECT NAME, DEPTNAME
FROM EMPLOYEE, DEPARTMENT
WHERE ’
EMPLOYEE.DEPTID=DEPARTMENT.DEPTID
AND SALARY>50000;

(iii) To display the names of employees whose salary is not known, in alphabetical order.
Answer:
SELECT NAME FROM EMPLOYEE
WHERE SALARY IS NULL
ORDER BY NAME;

(iv) To display DEPTID from the table EMPLOYEE without repetition.
Answer:
SELECT DISTINCT DEPTID FROM
EMPLOYEE

Question 12.
(i) Give two advantages and two disadvantages of star topology.
Or
Define the following terms:
(a) www
(b) Web hosting
Answer:
Advantages of Star Topology are:

• Ease of service All the data passes through the hub. The hub makes it easy to troubleshoot by offering a single point for error connection.
• Centralized control Computers are connected by cable segments to centralized component, called a hub or switch.

Disadvantages of Star Topology are:

• Long cable length Requires more cable than a linear bus.
• Difficult to expand Extra hardware is required (hubs or switches) which adds to cost.

Or
(a) WWW is a set of protocols that allow you to access any document on the internet through the naming systems based on URLs.
(b) Web hosting is a service that allows organizations and individuals to post a website or web page onto the server, which can be viewed by everyone on the Internet.

(ii) How is packet switching different from circuit switching?
Answer:
Differences between packet switching and circuit switching are as follows:

Packet Switching	Circuit Switching
It uses store and forward concept to send messages.	It does not follow store and forward concept.
Each data unit knows only the final receiver’s address.	Each data unit knows the entire path from sender to receiver.
No physical path is established in packet switching.	Physical connection is established between sender and receiver.

Question 13.
BeHappy Corporation has set up its new centre at Noida, Uttar Pradesh for its office and web-based activities. It has 4 blocks of buildings.

Distance between the various blocks is as follows:

A to B	40m
B to C	120m
C to D	100m
A to D	170m
B to D	150m
A to C	70m

Numbers of computers in each block
Block A – 25
Block B – 50
Block C -125
Block D -10
(i) Suggest and draw the cable layout to efficiently connect various blocks of buildings within the Noida centre for connecting the digital devices.
Answer:
Cable layout to efficiently connect various blocks

(ii) Suggest the placement of the following device with justification
(a) Repeater
(b) Hub/Switch
Answer:
(a) Repeater It is to be placed between block C and block D as the distance between them is 100 m.
(b) Hub/Switch It is to be placed in each block as they help to share data packets within the devices of the network in each block.

(iii) Which kind of network (PAN/LAN/WAN) will be formed if the Noida office is connected to its head office in Mumbai?
Answer:
WAN (Wide Area Network) will be formed if the Noida office is connected to its head office in Mumbai because the distance between these two cities is a few kilometers and in such a long distance, the Internet connectivity is required, and the Internet comes under Wide Area Network.

(iv) Which fast and very effective wireless transmission medium should preferably be used to connect the head office at Mumbai with the centre at Noida?
Answer:
Satellite is fast and very effective wireless transmission medium which should be used to connect the head office at Mumbai with the centre at Noida.

Students can access the CBSE Sample Papers for Class 12 Economics with Solutions and marking scheme Term 2 Set 10 will help students in understanding the difficulty level of the exam.

CBSE Sample Papers for Class 12 Economics Term 2 Set 10 for Practice

Time allowed: 2 Hours
Maximum Marks: 40

General Instructions:

• This is a Subjective Question Paper containing 13 questions.
• This paper contains 5 questions of 2 marks each, 5 questions of 3 marks each and 3 questions of 5 marks each.
• 2 marks questions are Short Answer Type Questions and are to be answered in 30-50 words.
• 3 marks questions are Short Answer Type Questions and are to be answered in 50-80 words.
• 5 marks questions are Long Answer Type Questions and are to be answered in 80-120 words.
• This question paper contains Case/Source Based Questions.

Question 1.
“Full employment implies zero unemployment when nobody is ever unemployed in the economy.” Defend or refute the statement with valid reason.
OR
“APS can be negative whereas MPS can never be negative.” Justify the statement. (2)

Question 2.
Given marginal propensity to save 0.25, what will be the increase in national income if investment increases by ₹ 125 crores. Calculate.
OR
S = – 100 + 0.2 Y is the saving function in an economy. Investment expenditure is ₹5,000. Calculate the equilibrium level of income. (2)

Question 3.
Nurse in a government hospital comes under the category of‘Regular Salaried Employee’. Justify the statement with valid reason. (3)

Question 4.
“Compared to females, more males are found to be working. The difference in participation rates is very large in urban areas.” Justify the statement with valid reason. (3)

Question 5.
“Environment and economy are inter¬dependent and need each other.” Justify the given statement with a valid argument.
OR
“The concept of sustainable development relates to development that doesn’t compromise the needs of the future generation.” Explain. (2)

Question 6.
Will the following be included in the domestic product of India? Give reasons for your answer.
(A) Profits earned by foreign companies in India.
(B) Salaries of Indians working in the Russian Embassy in India.
(C) Profits earned by a branch of State Bank of India in Japan.
OR
From the following information, compute GNP_MP.
GDP_FC = ₹ 2,000
Net factor income to abroad = ₹ 100
Indirect Taxes = ₹ 320
Subsidies = ₹ 100. (3)

Question 7.
Compare and contrast the development of India, China and Pakistan with respect to some salient human development indicators.

Some Selected Indicators of Human Development, 2017-2019


Note: * for the year 2011: for the year 2015.

Sources: Human Development Report 2019 and 2020 and Word Development Indicators (www.world in. org); Key indicators for Asia and the Pacific 2019. Asian development bank (ADB).

Read the following case carefully and answer question number 8 and 9 given below:

As per the Census 2001, the Indian workforce is over 400 million strong, which constitutes 39.1 % of the total population of the country. The workers comprise 312 million main workers and 88 million marginal workers (i.e., those who did not work for at least 183 days in the preceding 12 months to the census taking). Sex differential among the number of male and female worker in the total workforce is significant. Of the total 402 million workers, 275 million are males and 127 million females. This would mean that 51.7 percent of the total males and 25.6 percent of the total females are workers.

The number of female workers is about less than half the number of male workers. In terms of proportion, 68.4 percent of the workers are males and 31.6 percent females. Among the main workers, female workers, are only 23.3 % and 76.7% are male workers. Majority of female workers (87.3 percent) are from rural areas. This is also twice that of male workers, which may be due to their being employed predominantly in activities like cultivation and agricultural labour. In the urban areas, majority of female workers are engaged in Households industry and other work.

Question 8.
“If a person had worked as a daily wage labourer for four months, as an agricultural labourer for one month”. Identify the type of worker he will be considered? (3)

Question 9.
“The nature of employment in India is multifaceted.” Justify the statement. (3)

Question 10.
Why did China introduce structural reforms in 1978? (3)

Question 11.
(A) “Circular flow principle is based on the assumption that one’s expenditure will become other’s income.” Explain the given statement.
(B) “Gross Domestic Product (GDP) is not the best indicator of the economic welfare of a country.” Defend or refute the given statement with valid reasons. (5)

Question 12.
(A) Define the problem of double counting in the computation of national income.
(B) Calculate national income from the following data: (₹ in crores)
(i) Private final consumption expenditure 500
(ii) Net domestic fixed capital formation 100
(iii) Net factor income from abroad 30
(iv) Change in stock 20
(v) Net exports 40
(vi) Net indirect taxes 50
(vii) Mixed income 300
(viii) Government final consumption expenditure 200
OR
(A) Explain mixed income of self-employed. (2)
(B) Calculate Gross National Product at market price by expenditure method. (₹ in crores)
(i) Compensation of employees 100
(ii) Private final consumption expenditure 200
(iii) Rent 20
(iv) Government final consumption expenditure 50
(v) Profits 10
(vi) Interest 10
(vii) Gross domestic capital formation 60
(viii) Net imports 10
(ix) Consumption of fixed capital 20
(x) Net Indirect Taxes 30
(xi) Net factor income from abroad(-)20
(xii) Change in stocks 10
(xiii) Mixed income 110 (3)

13. Complete the following table:

Students can access the CBSE Sample Papers for Class 12 Economics with Solutions and marking scheme Term 2 Set 9 will help students in understanding the difficulty level of the exam.

CBSE Sample Papers for Class 12 Economics Term 2 Set 9 with Solutions

Time allowed: 2 Hours
Maximum Marks: 40

General Instructions:

• This is a Subjective Question Paper containing 13 questions.
• This paper contains 5 questions of 2 marks each, 5 questions of 3 marks each and 3 questions of 5 marks each.
• 2 marks questions are Short Answer Type Questions and are to be answered in 30-50 words.
• 3 marks questions are Short Answer Type Questions and are to be answered in 50-80 words.
• 5 marks questions are Long Answer Type Questions and are to be answered in 80-120 words.
• This question paper contains Case/Source Based Questions.

Question 1.
What happens to aggregate income in an economy in which intended saving exceeds intended investment?
OR
If in an economy investment is greater than saving, what is the effect on the national income? (2)
Answer:
Aggregate income will tend to fall when intended saving exceeds intended.
OR
If in an economy investment is greater than saving, the level of income will rise till full employment is achieved.

Question 2.
In an economy, investment increased by ₹1,100 and as a result of it, income increased by ₹5,500. Had the marginal propensity to save been 25 percent, what would have been the increase in income?
OR
If in an economy:
Change in initial Investments (Δl) = ₹500 crores
Marginal Propensity to Save (MPS) = 0.2
Find the values of the following:
(A) Investment multiplier (K)
(B) Change in final income (ΔY) (2)
Answer:

Question 3.
“GLF campaign met with many problems.” Elucidate. (2)
Answer:
GLF campaign met with many problems. A severe drought caused havoc in China killing about 30 million people. When Russia had conflicts with China, it withdrew its professionals who had earlier been sent to China to help in the industrialisation process.

Question 4.
“India has always had an advantage over Pakistan in some areas”. State any two such areas. (2)
Answer:
India has always had an advantage over Pakistan in some areas, such as

• having more trained labor
• making good investments in education
• improving basic health care facilities (Any two)

Question 5.
What was the aim of implementing Great Leap Forward campaign in China?
OR
Compare and analyze Indian and Chinese economy on the basis of below-given table:
Annual Growth of Gross Domestic Product (%), 1980 – 2017

Country	1980 – 90	2015 – 2017
India	5.7	7.3
China	10.3	6.8

Answer:
The main aim of’Great Leap Forward’ (GLF) in China was to ensure rapid increase of industries. The campaign is modeled on the development of major industries in the country. People were motivated about establishing industries in their backyards.
OR
When many developed countries were finding it difficult to maintain a growth rate of even 5 percent, China was able to maintain near double-digit growth during 1980s. In 2015 – 17, there has been a decline in China’s growth rate, whereas, India met with a moderate increase in growth rate.

Question 6.
Will the following be included in the national income of India? Give reasons for your answer.
(A) Financial assistance to flood victims.
(B) Profits earned by the branches of a foreign bank in India.
(C) Salaries of Indians working in the American Embassy in India.
OR
If the Real Gross Domestic Product is Rs. 250 and the price Index (base = 100) is 120, calculate the Nominal Gross Domestic Product. (3)
Answer:
(A) No. Financial assistance to flood victims are
not included as it is a transfer payment.
(B) No. It is a factor income to abroad.
(C) Yes. Included as it is a factor income from abroad so it is added to NDP to get Nl.
OR

Nominal Gross Domestic Product = ₹300

Question 7.
The following table shows distribution of workforce in India for the year 1972 – 73. Analyse it and give reasons for the nature of workforce distribution. You will notice that the data is pertaining to the situation in India 30 years ago.

Place of Residence	Workforce (in millions)		Total
	Male	Female
Rural	125	70	195
Urban	32	7	39

Read the following case carefully and answer question number 8 and 9 given below:

India’s ambition of sustaining its relatively high growth depends on one important factor: infrastructure. The country, however, is plagued with a weak infrastructure incapable of meeting the needs of a growing economy and growing population. S&P Global Ratings projects India’s GDP to grow around 8% for the next three fiscal years, among the fastest in large, growing economies. The government also aims to significantly boost the manufacturing sector to contribute an all-time high of about 25% of GDP by 2025, from below 16% currently.

India is striving to improve its manufacturing competitiveness at a time when manufacturing powerhouse China is shifting toward consumption-led growth. China now faces the risk of overcapacity in segments such as port and power. For India, on the other hand, its road to sustainably higher growth and a competitive manufacturing sector goes through robust and reliable national infrastructure, especially in power and transportation.
Answer:
In 1972-73:
(A) Pre dominance of agriculture as out of total workforce of 234 million, 195 million was in rural areas and only 39 million in urban areas.

(B) More male workers both in urban and rural areas as only 77 million female workers were there as compared to 157 million male workers.

(C) Less female workers in both rural and urban areas. Also, female workers were much lesser in urban areas. In rural areas, males accounted for 125 million workforce and women 70 million of work force. In urban areas, 32 million males formed the workforce whereas women workforce was only 7 million.

Question 8.
“Infrastructure is often called as the lifeline of the economy.” Explain in the context of above case. (3)
Answer:
Infrastructure is often called as the lifeline ofthe economy. Infrastructure provides supporting services in the main areas of industrial and agricultural production, domestic and foreign trade and commerce. It helps in increasing the productivity of the factors of production and enhancing the quality of life. Infrastructure is also critical for achieving manufacturing competitiveness.

Question 9.
“Infrastructural facilities are mainly built or run by the government and public sector enterprises.” Defend or refute the statement with valid reason? (3)
Answer:
Building of infrastructure requires Large and lumpy investment and has a relatively long gestation period. Due to this fact, infrastructural facilities are either built or run by the government and public sector enterprises and if private sector is permitted to make investments and run infrastructural projects, they must be regulated in order to ensure quality infrastructure to one and all in the society.

Question 10.
Do you think that in the last 50 years, employment generated in the country is commensurate with the growth of GDP in India? How? (3)
Answer:
During the period 1950-2010, the Gross Domestic Product (GDP) of India grew positively and was higher than the employment growth. However, there was always a fluctuation in the growth of GDP. During this period, employment grew at the rate of not more than 2 percent.

In the late 1990s: employment growth started declining and reached the level of growth that India had in the early stages of planning. During these years, we also find a widening gap between the growth of GDP and employment. This means that in the Indian economy, without generating employment, we have been able to produce more goods and services. This refers as jobless growth.

Question  11.
Given the following data, find the missing value of ‘Government Final Consumption Expenditure’ and ‘Mixed-Income of Self Employed’.

Particulars	Amount (in ₹ crores)
National Income	71,000
Gross Domestic Capital Formation	10,000
Government Final Consumption Expenditure	?
Mixed-Income of Self-Employed	7
Net Factor Income from Abroad	1,000
Net Indirect Taxes	2,000
Profit	1,200
Wages and Salaries	15,000
Net Exports	5,000
Private Final Consumption Expenditure	40,000
! Consumption of Fixed Capital	3,000
Operating Surplus	30,000

Given the following data, find the values of ‘Operating Surplus’ and ‘Net Exports’:

Particulars	Amount (in ₹ crores)
Wages and Salaries	2,400
National Income	4,200
Net Exports	?
Net Factor Income from Abroad	200
Gross Domestic Capital Formation	1,100
Mixed-Income of Self-Employed	400
Private Final Consumption Expenditure	2,000
Net Indirect Taxes	150
Operating Surplus	?
Government Final Consumption Expenditure	1,000
Consumption of Fixed Capital	100
Profits	600

Answer:
Mixed income of self-employed = (i) – [(viii) + (xii) + (v)]
= 71,000 – (15,000 + 30,000 + 1,000)
Mixed income of self-employed = ₹25,000 crores
Government Final consumption expenditure = (D – [(x) + (ii) + (v) + (ix)] + (vi) + (xi)
= 71,000 – (40,000 + 10,000 + 1,000 + 5,000) + 2,000 + 3,000
= ₹20,000 crores
OR
Operating surplus = (ii) – (iv) – (vi) – (i)
= 4200 – 200 – 400 – 2400 = 1200 crores
Net exports = (ii) – (vii) – (x) – (v) + (xi) + (viii) – (iv)
= 4200 – 2000 – 1000 – 1100 + 100 + 150 – 200
= ₹150 crores

Question 12.
(A) How does increase in inequalities in distribution of income affect welfare of the society? Explain.

(B) “Higher Gross Domestic Product (GDP) means greater per capita availability of goods in the economy.” Do you agree with the given statement? Give valid reason in support of your answer. (5)
Answer:
(A) Increase in inequalities means that rich become richer and poor become poorer. Since utility of money is higher among poor and Lower among the rich, any increase in inequalities may not lead to increase in welfare.

(B) “Higher Gross Domestic Product (GDP) means greater per capita availability of goods in the economy.” This statement is not true.

1. If the rate of population growth is more than the rate of growth of GDP, the per capita availability of goods and services will fall.
2. GDP doesn’t account for changes in inequalities in distribution of Income. If the rising GDP is concentrated in a few hands, per capita availability of goods in the economy might not increase.

Question 13.
Explain determination of equilibrium level of national income using aggregate demand and aggregate supply approach. Use diagram. Also explain the effect when aggregate demand is less than aggregate supply. (5)
Answer:

The equilibrium is where AD = AS i.e. at point E where AD curve intersects the 450 line. OM is the equilibrium income.

When AD is less than AS, inventories accumulate. The producers produce less. This continues till AS falls enough to be equal to AD.

Students can access the CBSE Sample Papers for Class 12 Biology with Solutions and marking scheme Term 2 Set 8 will help students in understanding the difficulty level of the exam.

CBSE Sample Papers for Class 12 Biology Standard Term 2 Set 8 with Solutions

Time Allowed: 2 Hours
Maximum Marks: 40

General Instructions:

• All questions are compulsory.
• The question paper has three sections and 13 questions. All questions are compulsory.
• Section-A has 6 questions of 2 marks each; Section-B has 6 questions of 3 marks each, and Section-C has a case-based question of 5 marks.
• There is no overall choice. However, internal choices have been provided in some questions. A student has to attempt only one of the alternatives in such questions.
• Wherever necessary, neat and properly labeled diagrams should be drawn.

SECTION – A
(Section A has 6 Questions of 2 marks each.)

Question 1.
(A) It is always advised that breastfeeding is best for the newborn as breastfed babies tend to be more immune than the bottle-fed babies. Why?
(B) What do you mean by anamnestic response? (2)
Answer:
(A) Mother’s milk especially the colostrum (yellowish fluid) secreted during initial days of lactation by the mother which contains abundant antibodies (IgA) that gives protection to the infant. These antibodies are not available to the bottle-fed babies.

Related Theory:
When such ready-made antibodies are directly given to an individual to protect the body against foreign substances. Such kind of immunity is called as passive immunity. This type of immunity is fast-acting but it lasts for only few days/months.

(B) The anamnestic response is also known as secondary or booster immune response that occurs due to second or subsequent encounter with the same pathogen. As compared to a primary immune response which is of low intensity, the secondary response is highly intensified with a shorter lag period and greater production of antibodies and it lasts longer.

Question 2.
(A) Anshika’s mother explained her the formation of bread by showing the following pictures of the rising of the dough. Which microorganism is used for fermenting the dough in the making of bread?

(B) What do you mean by toddy?
OR
Mention the role of baker’s yeast in the production of bread. (2)
Answer:
(A) For making bread, the dough is fermented using baker’s yeast, Saccharomyces cerevisiae.
(B) Toddy is a traditional drink of some parts of southern India which is made by fermenting sap from palm trees, coconut, etc.
OR
Saccharomyces cerevisiae, also known as Baker’s yeast, is responsible for the alcoholic fermentation of sugars in wheat flour, that produce ethanol and CO₂. CO₂ raises the bread when baked and makes it soft.

Question 3.
The given picture shows a keystone species – sea otter along with other species like kelp and sea urchin. What do you mean by keystone species and what is its importance? (2)

Answer:
A keystone species is an organism which helps to define an entire ecosystem. It plays vital role in sustaining the community. The ecosystem would be dramatically different or cease to exist altogether, without its keystone species. This means that if the species disappear from the ecosystem, no other species would be able to fill its ecological niche.
Example: Sea otter is the keystone species and in its absence, the sea urchins overgraze kelp and destroy the kelp forest community.

Question 4.
People usually discriminate individuals suffering from AIDS due to certain misconceptions and finally it leads to social boycott of such individuals.
Do you think this is ethically correct? If not, why? Suggest one preventive measure for the disease. (2)
Answer:
No, it is not ethically correct at all. An individual suffering from AIDS should not be discriminated as it is like any other disease. AIDS is not contagious, i.e., it does not spread by shaking hands, talking or using common utensils.

Preventive measures are as follows:

• Making blood (from blood banks) safe from HIV.
• Use of only disposable needles and syringes in public and private hospitals and clinics is ensured.
• Condoms are distributed free of cost and safe sex is being advocated.
• Controlling drug abuse.
• Promotion of regular check-ups for HIV in susceptible populations. (Anyone)

Question 5.
Describe the chemical method of making cells competent for transformation with recombinant DNA.
OR
Which category of enzymes is termed as ‘molecular glue’ and why? (2)
Answer:
In the chemical method or CaCl₂ method, the cells are treated with a specific concentration of a divalent cation, such as calcium, that increases the efficiency with which the DNA enters through the pores present in the bacterial cell walls. Recombinant DNA is then forced into such cells by incubating the cells with recombinant DNA on ice first, and then they are given heat shock by placing them at 42°C for a short duration, and then putting them back on ice. This enables the bacteria to take up the recombinant DNA.
OR
DNA ligases are termed as ‘molecular glue’ as they repair broken DNA by joining two nucleotides.
It is used in rDNA technology or genetic engineering to reverse the action of restriction enzymes by joining the complementary DNA strands or ends together. Example: T₄ DNA Ligase.

Question 6.
During a visit to a national park, teacher was explaining about ecological niche, habitat, etc., specify the difference between an ecological niche and habitat. (2)
Answer:
The difference between an ecological niche and habitat is as follows:

Niche	Habitat
It is defined as the particular area within a habitat or physical space occupied by an organism. Niche of an organism comprises of an invariably defined range of conditions that the organism can tolerate, diversity in the resources it utilises and a distinct physical and functional rote in the ecological system.	It refers to a specific space or place where in an organism Lives, grows, adapts and reproduces. Various abiotic factors like temperature, sunlight. rainfall types of soil, etc., determine the presenœ of organisms present in an area.

SECTION – B
(Section B has 6 Questions of 3 marks each.)

Question 7.
(A) What do you mean by Bioconversion?
(B) Name two commonly used vectors in rDNA technology.
(C) How many fragments will be produced when a linear DNA and a plasmid DNA having three restriction sites for EcoRI are cut with the restriction enzyme? (3)
Answer:
(A) Bioconversion refers to the process by which organic materials such as plant or animal waste are converted to specific usable products by biological processes or microbial, activity.
(B) The two commonly used vectors in rDNA technology are Plasmid and Bacteriophage.
(C) Number of fragments produced in linear DNA are 4. Number of fragments produced in a plasmid are 3.

Question 8.
There is always an increasing demand of food supply in our country. A farmer has mainly three options to increase the food production. List these three options. (3)
Answer:
To increase the food production there are following three options:

1. Agro-chemical-based agriculture.
2. Organic agriculture.
3. Genetically engineered crop-based agriculture.

Question 9.
The following pictures show the symptoms of some diseases such as sneezing in case of common cold and skin rash in case of chikungunya. Write the mode of transmission of infection for the following diseases: (3)
(A) Common cold
(B) Chikungunya
(C) Ascariasis

Answer:
The mode of transmission of infection for the following diseases is as follows:

Disease	Mode of transmission
Common cold	It spreads through droplets resulting from cough or sneezes of an infected person (droplet infection) or through contaminated objects such as pens, books, cups, doorknobs, computer keyboard or mouse, etc.
Chikungunya	It is transmitted by the bite of Aedes aegypti mosquito.
Ascariasis	Gets transmitted when a healthy person consumes water, vegetables, fruits, etc., or gets exposed to soil, water, plants, etc., that are contaminated with the fecal matter of infected persons contains eggs of the parasite.

Question 10.
Suresh was observing that in a field, insects were not able to infect the plants, instead, insects were killed on eating the plants. Explain the reason why it happened? Give some examples of such crops. (3)
Answer:
When the insects were not able to infect the plants and were getting killed upon eating them is because of a reason that such plants are geneticalLy modified pest-resistant plants that produce a toxin that kills insects when they feed on them.

Bacillus thuringiensis (Bt) is a bacterium that produces a toxin named Bt toxin. This toxin is fatal for insects, therefore, Bt-toxin gene has been cloned from the bacteria and expressed in plants to provide resistance to insects without the need for insecticides. Thus, it is called as a biopesticide.
Examples: Bt cotton, Bt corn, Bt rice, Bt tomato, Bt potato, and Bt soybean, etc.

Question 11.
Which are the three types of age pyramids? Depict each of them with a diagram. (3)
Answer:
The age pyramids can be classified into three categories:

• Expanding or growing
• Stable
• Declining

Related Theory
Age pyramid is formed when the age distribution i.e., percent individuals of a given age or age group is plotted for the population.

Question 12.
Elaborate with the help of examples that alien species are highly invasive and are a threat to indigenous species.
OR
List any three consequences of the loss of biodiversity? (3)
Answer:
It has been seen for a long time that when alien species are introduced unintentionally or deliberately for any purpose, some of them become invasive, and cause decline or extinction of indigenous species.
Example:
(i) In East Africa, introduction of the Nile perch into Lake Victoria eventually led to the extinction of an ecologically unique assemblage of more than 200 species of cichlid fish in the lake.
(ii) In India, the introduction of the invasive weed species like carrot grass (Parthenium), Lantana and water hyacinth (Eichhornia) led to the environmental damage and posed a threat to our native species.
(iii) The recent illegal’ introduction of the African catfish Clarias gariepinus for aquaculture purposes is posing a threat to the indigenous catfishes in Indian rivers.
OR
The consequences of loss of biodiversity:
(i) Declining biodiversity lowers the quality of the ecosystem’s services which often include maintaining the soil, purifying water that runs through it, and supplying food and shade, etc.
(ii) Loss of biodiversity results in the extinction of many species.
(iii) Human beings are very much dependent on biodiversity for food and other requirements, therefore, its loss will be hard-pressed for mankind.

SECTION – C
(Section C has a case-based question of 5 marks.)

Question 13.
In order to spread awareness regarding organic farming, students pasted the following posters inside and outside the school campus. answer the following Based on this questions:

(ii) How do organic farmers manage fertility?
(B) How are crop damage by insect pests managed on organic farms?
OR
(A) (I) What is organic agriculture?
People extensively use antibiotics for the treatment of several diseases. Komal knows that antibiotics are produced by microbes and are very useful to treat many diseases Based on this answer the following questions:

(A) What are antibiotics?
(B) How does antibiotic resistance happen?
(C) What precautions must be taken while taking antibiotics? List any two. (5)
Answer:
(A)

• Organic agriculture is a system of farming that mimics natural ecosystems. It balances pest and beneficial organism population and maintains and replenishes fertility of the soil.
• Organic farmers manage fertility or crop nutrients through crop rotation, which includes application of plant and animal organic matter, generally in the form of compost. Soil structure, organic matter content and soil microbial life is improved by appropriate tillage and cultivation practices.

(B) In organic farming crop damage by insect pests is prevented primarily through the use of natural pesticides (mainly extracted from plant or animal origins), biological and cultural practices such as crop rotation; habitat management; beneficial organism releases; sanitation; and timing.
OR
(A) Antibiotics are the chemical substances that are produced by some microbes and can kill or retard the growth of other (disease-causing) microbes.

(B) On exposure to antibiotics, bacteria can develop ways to escape their effects. We should be careful about how we use antibiotics because bacteria are able to adapt. Using antibiotics when they are not necessary may cause them to become ineffective when they are really needed. A person does not become resistant to an antibiotic, but the bacteria become resistant to treatment.

(C) The precautions that should be taken while taking antibiotics are:

• Antibiotics should be taken only when advised by a qualified doctor.
• A person must complete the full course of antibiotics as prescribed by doctor.
• Antibiotics should be taken in proper doses.
• Antibiotics should not be taken unnecessarily as it can kill the useful bacteria in the body.

Students can access the CBSE Sample Papers for Class 12 Biology with Solutions and marking scheme Term 2 Set 7 will help students in understanding the difficulty level of the exam.

CBSE Sample Papers for Class 12 Biology Standard Term 2 Set 7 with Solutions

Time Allowed: 2 Hours
Maximum Marks: 40

General Instructions:

• All questions are compulsory.
• The question paper has three sections and 13 questions. All questions are compulsory.
• Section-A has 6 questions of 2 marks each; Section-B has 6 questions of 3 marks each; and Section-C has a case-based question of 5 marks.
• There is no overall choice. However, internal choices have been provided in some questions. A student has to attempt only one of the alternatives in such questions.
• Wherever necessary, neat and properly labeled diagrams should be drawn.

SECTION – A
(Section A has 6 Questions of 2 marks each.)

Question 1.
(A) Why does a person shivers considerably while suffering from malaria?
(B) Who established that the malarial parasite is transmitted by the bite of a female Anopheles mosquito?
OR
Why intake of cannabinoids is banned in sports and games? (2)
Answer:
(A) The parasites (sporozoites) infect RBCs and rupture them which results in the release of a toxic substance called as haemozoin. This toxin is responsible for the chill (shivering) and high fever recurring every three to four days in malaria.

(B) Sir Ronald Ross.

Related Theory
Sir Ronald Ross of the Indian Medical Service, established on 29th August, 1897 that malarial parasite is transmitted by the bite of a female Anopheles mosquito.
OR
The intake of cannabinoids is banned in sports and games because sportspersons misuse these drugs to enhance their performance. In order to increase muscle strength and bulk and to promote aggressiveness, the sportspersons misuse narcotic analgesics, anabolic steroids, diuretics and certain hormones in sports, that leads to an increase in their athletic performance. This can negatively affect their general health and in long run can hamper the normal functioning of organ systems.

Question 2.
Write any two benefits that Lactic Acid Bacteria (LAB) provides. (2)
Answer:
The two benefits of Lactic Acid Bacteria (LAB) are:

1. LAB increases the nutritional quality of curd by increasing the amount of Vitamin B₁₂
2. It checks the growth of disease-causing organisms in the gut.

Question 3.
Roma was confused after hearing about
red data book which is shown in the picture below. She thinks it to be a storybook. To clear her confusion, explain briefly what do we mean by red data book. When and who initiated the red data book? (2)

Answer:
A Red Data Book is a document that keeps a record of all the rare and endangered species of animals, plants and fungi. IUCN red list of threatened species is an inventory of global conservation status of biological species, which is compiled in Red Data Book.

IUCN established the Red Data Book to safeguard the rare species of flora and fauna on Earth, so as to prevent their extinction and it was initiated in 1964.

Related Theory
Red Data Book has its origins from Russia. But at the present time, the International Union for Conservation of Nature (IUCN) maintains the Red Data Book. The IUCN was founded in 1948 with an aim to maintain a complete record of every species that ever lived and it works in the field of nature conservation and sustainable use of natural resources.

Question 4.
During sewage treatment, list the events that Lead to a significant reduction in Biochemical Oxygen Demand (BOD) of a primary effluent. (2)
Answer:
The primary effluent produced during primary treatment is passed into large aeration tanks, where it is constantly agitated mechanically and air is pumped into it. This leads to vigorous growth of useful aerobic microbes into floes. The organic matter in the effluent is consumed by these microbes, thereby, decreasing BOD (Biochemical Oxygen Demand) of the effluent.

Related Theory
Floes are masses of bacteria associated with fungal filaments to form mesh like structures. During their growth, the major part of the organic matter in the effluent is consumed by these microbes and converted into microbial biomass. As a result, the BOD (Biochemical Oxygen Demand) of the effluent is significantly reduced.

Question 5.
How the technique of PCR serves as an important tool for early diagnosis of an infectious disease? (2)
Answer:
The technique of PCR, i.e., Polymerase chain reaction is very effective and thus it enables the specific amplification of the desired DNA from a limited amount of DNA template. Therefore, it can detect the presence of an infectious organism in the infected patient at an early stage of infection, even before the infectious organism has multiplied to a large number.

Related Theory
Technique of PCR is routinely used to detect HIV in suspected AIDS patients and also used to detect mutations in genes in suspected cancer patients.

Question 6.
The following picture depicts an insect that closely resembles a leaf. What is this phenomenon called as? How does this phenomenon help an insect?

OR
Give the difference between the two main branches of ecology. (2)
This phenomenon is called as camouflage. Camouflage or cryptic colouration is a type of defense mechanism that gives the organisms like insect, the ability to blend or merge with the surroundings or background. This helps them to conceal their presence or identity in order to avoid being detected easily by the predator or to deceive their prey.
OR
The two main branches of ecology are autecology and synecology and the difference between them are:

Autecology	Synecology
It is the study of individual organism or individual species. It is also known as population ecology.	It is the study of group of organisms of different species in a community. It is also known as community ecology.

SECTION – B
(Section B has 6 Questions of 3 marks each.)

Question 7.
(A) The following microbes share a common characteristic. List that characteristic. Aspergillus niger, Clostridium butylicum and Lactobacillus.
(B) Why in the treatment of waste water rich in organic matter, aerobic degradation is more important than anaerobic degradation? (3)
Answer:
(A) The common characteristic of the microbes Aspergillus niger, Clostridium butylicum and Lactobacillus is that they all produce organic acids as a part of their metabolism and thus are useful for commercial and industrial production.

Related Theory
Aspergillus niger (a fungus) produces citric acid, Clostridium butylicum (a bacterium) produces butyric acid and Lactobacillus (a bacterium) produces lactic acid.

(B) The aerobic heterotrophic bacteria bring aerobic degradation of sewage. During their vigorous growth, the aerobic microbes consume a major part of the organic matter and thus reduce the BOD significantly. Therefore, aerobic degradation is more important.
Whereas anaerobic degradation is done after the aerobic degradation (where the BOD is already pulled down below a threshold level). In anaerobic degradation, only the bacteria and fungi (present in the floes) in the activated sludge are digested and anaerobic bacteria produce a mixture of gases such as methane, hydrogen sulphide and carbon dioxide. Therefore, it is less important.

Question 8.
(A) It is very essential to make host cells competent so that they can take up the desired DNA. Describe the two physical methods of making the cells competent for transformation with recombinant DNA.
(B) Expand – cDNA and Bt. (3)
Answer:
(A) The two different physical methods for
making the cells competent are:

1. Micro-injection: In this method the recombinant DNA is directly injected into the nucleus of an animal cell.
2. Biolistics or gene gun: This method includes physical introduction of foreign DNA in cells and is suitable for plants.

In this method the cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA.

(B) cDNA – Complementary DNA, Bt – Bacillus thuringiensis.

Question 9.
The introduction of genetically engineered lymphocytes into an ADA deficiency patient served as a cure but it was not a permanent cure. Why? Suggest a possible permanent cure. ?(3)
Answer:
Genetically engineered lymphocytes are created by taking lymphocytes from the blood of ADA deficient patients and grown in a culture. With the help of a retroviral vector, a functional ADA cDNA is then introduced into the lymphocytes. Then these lymphocytes are returned to the patients. Most of the lymphocytes are short lived having an average lifespan of a week to a few months. Since lymphocytes are not immortal, therefore, the patients require periodic infusion of such genetically engineered lymphocytes.

A permanent cure of ADA deficiency is to isolate a normal functioning gene producing ADA from the marrow cells and to introduce them into the cells at early embryonic stages. The lymphocytes of bone marrow then contain the functional ADA gene and reactivate the patient’s immune system.

Related Theory
Adenosine deaminase deficiency is an autosomal recessive metabolic disorder that causes immuno deficiency.

Question 10.
Water is used by every cell of our body and thus it is very essential for life. List any three features of plants that help them to survive in water scarce environment. (3)
Answer:
The features of plants that help them to survive in water scarce environment are:

• They have a thick cuticle on their leaf surfaces and have sunken stomata (arranged in deep pits) to minimize water loss through transpiration.
• They follow a special photosynthetic pathway known as Crassulacean Acid Metabolism (CAM) that enables their stomata to remain closed during day time. This also minimize water loss through transpiration.
• Absence of leaves in some desert plants like Opuntia in which the leaves are reduced to spines to reduce water loss and the photosynthetic function is taken over by the flattened stems. The stem is green, succulent and fleshy.
• The roots of these plants grow very deep in search of available underground water.
  (Any three)

Question 11.
It is observed that tropical regions have greater biodiversity as compared to temperate regions. Briefly explain the reasons responsible for it.
OR
How does the loss of biodiversity in a particular region affect that region? (3)
Answer:
The tropical regions have greater biodiversity as compared to temperate regions because of the following reasons:

• Speciation is generally a function of time. The temperate regions were subjected to frequent glaciations in the past whereas the tropical latitudes remained relatively undisturbed for millions of years and therefore the tropics got a long evolutionary time for species diversification.
• The Tropical environments are less seasonal as compared to temperate environments and are relatively more constant and predictable. Therefore, niche specialization is promoted in such constant environments which lead to a greater species diversity.
• More amount of solar energy is available in the tropics which contributes to higher productivity and thus lead to greater diversity.
• The resource availability is higher and rate of extinction is low in tropics.

OR
Loss of biodiversity in a region may lead to:

• Decline in plant production.
• Lowered resistance to environmental disturbances; like drought.
• Increased variability in certain ecosystem processes, example – plant productivity, water use, etc.

Question 12.
Describe the structure and the process of activation of human insulin with the help of a well labelled diagram. (3)
Answer:
Insulin consists of two short polypeptide chains, i.e., chain A and chain B, which are Linked together by disulfide bridges.

Insulin is synthesized as a pro-hormone in mammals including humans. It contains an extra stretch called the C peptide. The C peptide is absent in mature insulin and therefore it is removed during maturation into insulin.

Related Theory
Pro-hormone is the form of hormone which needs to be processed before it becomes a fully mature and functional hormone.

SECTION – C
(Section C has a case-based question of 5 marks.)

Question 13.
Any individual can suffer from cancer, although the risk goes up with age. But the risk depends on factors such as smoke, Lifestyle choices such as eating habits, frequency of exercise, family history of cancer, etc. Given below is a picture showing a comparison between a normal cell and a cancerous cell.

(A) Define cancer.
(B) Give the difference between benign tumours and malignant tumours.
(C) Write about any two diagnostic techniques to detect cancer.
OR
A 34-year-old woman showed the symptoms of sudden onset of fever, crippling joint pains, lymphadenopathy. The following picture shows one of the symptoms of the disease.
Based on the following picture and description answer the following questions:

(A) Based on the above mentioned symptoms, name the disease. How can this disease be prevented?
(B) List two ways by which vector-borne diseases can be prevented.
(C) What are pathogens? How do they enter our body? (5)
Answer:
(A) Cancer is a disease that is characterised by uncontrolled division of cells in a part of body that spreads to other parts of the body through blood and lymph.

(B) Benign tumours: These kinds of tumours remain confined to their original Location and thus, do not spread to the other parts of the body. Such tumours cause Little damage.
Malignant tumours: These tumours are a mass of proliferating cells called as neoplastic or tumour cells. These cells invade and damage the surrounding normal tissues/cells .by growing very rapidly.

(C) Cancer can be detected by the following methods:

• Biopsy: In this method a piece of the suspected tissue is cut into thin sections and then it is stained and examined under microscope by a pathologist. Such a study is termed as histopathological study.
• Radiography involves the use of X-rays to detect cancer of the internal organs.
• Computed – tomography (CT) uses X-rays to generate a three-dimensional image of the internal tissue.
• Magnetic Resonance Imaging (MRI) uses strong magnetic fields and non-ionising radiations to accurately detect pathological and physiological changes in the living tissue.
• Monoclonal antibodies are the antibodies against cancer-specific antigens that are used to detect certain cancers. (Any two)

OR
(A) Based on the mentioned symptoms, the disease’s name is chikungunya. This disease can be prevented by elimination of mosquitoes and their eggs.

(B) Vector-borne diseases can be prevented by:

• avoiding stagnation of water in and around residential areas.
• regular cleaning of household coolers.
• use of mosquito nets.
• introducing fishes like Gambusia in ponds that feed on mosquito larvae
• spraying of insecticides in ditches, drainage areas and swamps, etc.
• doors and windows should be provided with wire mesh to prevent the entry of mosquitoes.
  (Any two)

(C) Pathogens are defined as the disease- causing organisms. These include bacteria, viruses, fungi, protozoans, helminths, etc. The pathogens enter our body through different means such as air, water, soil, food, etc., and start multiplying and interfering with our normal vital activities.