CBSE Class 12 Biology Question Paper 2021 Set A Solved

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Access and download CBSE Class 12 Biology Question Paper 2021 Set A Solved, carefully designed as per the latest 2025-26 examination guidelines issued by CBSE, NCERT, and KVS. These Class 12 Biology previous year question papers include detailed solutions, helping students to assess their performance and identify and improve key areas before the final exams.

Solved Biology Question Papers for Class 12

Practicing these Class 12 Biology question papers is the best way to understand the actual exam pattern and marking scheme. By solving these papers under timed conditions, Class 12 students can improve their speed and accuracy. Download the full CBSE Class 12 Biology Question Paper 2021 Set A Solved to begin your self-assessment today.

Biology Class 12 Question Paper PDF with Solutions

SECTION A

1 A male honeybee has 16 chromosomes whereas its female has 32 chromosomes. Give one reason. 
 
2 How can an alien piece of DNA made to multiply in a host cell? 
 
3 If adenine constitutes 30% of an isolated DNA fragment, then what is the expected % of the base cytosine in it?
 
4 Name the vector of Chikungunya disease. 
 
5 Jhum cultivation has been in practice from earlier days, but it’s considered more problematic these days. Why?
 
OR
 
How is competition avoided in Nature? Give example.
 
SECTION B
 
6 Differentiate between inbreeding and out breeding in animals. 
 
7 What is meant by germplasm Collection? Describe its significance in plant breeding programmes.
 
OR
 
Name two alcoholic drinks produced in each of the following ways. (i) With distillation and (ii) without distillation.
 
8 Categories the following pairs of examples as convergent or divergent evolutions:
(a) Eyes of octopus and mammals. (b) Wings of butterfly and birds. (c) Tuber of sweet potatoes and potato. (d) Thorns in bougainvillea and tendrils in cucurbits.
 
9 How does geitonogamy differ from xenogamy in plants? 
 
10 Mention two applications of biotechnology in medicine with examples. 
 
11 Monocistronic structural genes in eukaryotes have interrupted coding sequences, Explain. How are they different in prokaryotes?
 
12 Name two types of animals based on their temperature tolerance. 
 
SECTION C
 
13 a) Taking one example each of habitat loss and fragmentation, explain how the two are responsible for biodiversity loss. b) Explain two different ways of biodiversity conservation.
 
14 How is Agrobacterium tumifaciens used in rDNA technology? Explain what and how are other pathogens are used for the purpose ?State two other methods by which host organism can be transformed?
 
15 How did Darwin theory of natural selection explain the appearance of new forms on the earth? 3
 
16 How do mycorrhizae function as biofertilisers? Explain with example. Name one cyanobacteria that can be used as a biofertiliser.
 
17 Explain the role of S and P in the experiments conducted by Hershey and chase?
 
OR
 
Explain the mechanism of sex determination in honeybees.
 
18 Explain different phases of spermatogenesis with schematic representation.
 
OR
 
Mention any three differences between spermatogenesis and oogenesis.
 
19 Describe the three different practices under natural methods of birth control. 
 
20 After a rainy day Shruti found many dragonflies flying over stagnant water. She thinks these flies come to drink water. i) Is Shruti’s explanation correct? Give your views
ii) Write the significance of your view in organic farming.
 
OR
 
What is biochemical oxygen demand (BOD) test? At what stage of Sewage treatment this test is performed? BOD level of three samples of water labeled as A, B and C are 30 mg/ L, 10mg/L and 500 mg/L respectively. Which sample of water is most polluted?
 
21 How is Biotechnology used to produce Bt cotton? Explain.
 
22 You have observed that fruit juice in bottles bought from the market is clearer as compared to those made at home. Give reason. Suggest a similar application in the field of detergent industry.
 
23 What are the producers in grass land and oceans .How is GPP different from NPP? Why is the productivity in oceans lesser than on land?
 
24 What will be the genotype and phenotype of the offspring if a colour blind man marries a carrier woman? Show the cross.
 
OR
 
How do histones acquire positive charge?
 
SECTION D

25 With a flow chart explain the process of decomposition .What factors affect this process?
 
OR
 
In Arcata, the town’s people have created an integrated waste water treatment process within a natural system. A citizen group called FOAM helps in upkeep of this project. (a) What are the main steps in waste water management done in this way? (b) .Ecosan. in Kerala and Sri Lanka is also an initiative for water conservation. How?
 
26 Explain the various phases of menstrual cycle with reference to changes in ovary and uterus and hormonal cycle.
 
OR
 
Continued self-pollination result in inbreeding depression. What are the out breeding devices developed in flowering plants to discourage self-pollination? Which type of pollination seen in Papaya?
 
27 What is a point mutation? Illustrate using the example of Sickle cell anaemia. Give the genotypes of a career and a sickle celled person.
 
OR
 
Explain the role of RNA polymerase in transcription in bacteria.


Please click on below link to downloadCBSE Class 12 Biology Question Paper 2021 Set A Solved

2024
CBSE Class 12 Biology Question Paper 2024 Solved
2023
CBSE Class 12 Biology Question Paper 2023 Solved
2022
CBSE Class 12 Biology Question Paper 2022 Set A Solved
CBSE Class 12 Biology Question Paper 2022 Set B Solved
CBSE Class 12 Biology Question Paper 2022 Set C Solved
CBSE Class 12 Biology Question Paper 2022 Set D
2021
CBSE Class 12 Biology Question Paper 2021 Set A Solved
CBSE Class 12 Biology Question Paper 2021 Set B Solved
CBSE Class 12 Biology Question Paper 2021 Set C Solved
CBSE Class 12 Biology Question Paper 2021 Set D Solved
2020
CBSE Class 12 Biology Boards 2020 Question Paper Solved Set A
CBSE Class 12 Biology Boards 2020 Question Paper Solved Set B
CBSE Class 12 Biology Boards 2020 Question Paper Solved Set C
CBSE Class 12 Biology Boards 2020 Question Paper Solved Set D
CBSE Class 12 Biology Boards 2020 Question Paper Solved Set E
CBSE Class 12 Biology Compartment Question Paper Solved 2020 Set A
CBSE Class 12 Biology Compartment Question Paper Solved 2020 Set B
CBSE Class 12 Biology Question Paper 2020 Set A
CBSE Class 12 Biology Question Paper 2020 Set B
CBSE Class 12 Biology Question Paper 2020 Set C Solved
CBSE Class 12 Biology Question Paper 2020 Set D Solved
2019
CBSE Class 12 Biology For Blind Question Paper Solved 2019
CBSE Class 12 Biology Question Paper 2019 Set A
CBSE Class 12 Biology Question Paper 2019 Set D
CBSE Class 12 Biology Question Paper 2019 Set E
CBSE Class 12 Biology Question Paper 2019 Set F
CBSE Class 12 Biology Question Paper 2019 Set H
CBSE Class 12 Biology Question Paper 2019 Set I
CBSE Class 12 Biology Question Paper 2019 Set K
CBSE Class 12 Biology Question Paper 2019 Set L
CBSE Class 12 Biology Question Paper 2019 Set N
CBSE Class 12 Biology Question Paper Solved 2019 Set B
CBSE Class 12 Biology Question Paper Solved 2019 Set C
CBSE Class 12 Biology Question Paper Solved 2019 Set G
CBSE Class 12 Biology Question Paper Solved 2019 Set J
CBSE Class 12 Biology Question Paper Solved 2019 Set M
2018
CBSE Class 12 Biology Board Question Paper Solved 2018 Set 1
CBSE Class 12 Biology Board Question Paper Solved 2018 Set 2
CBSE Class 12 Biology Board Question Paper Solved 2018 Set 3
CBSE Class 12 Biology Compartment Question Paper Solved 2018 Set 1
CBSE Class 12 Biology Compartment Question Paper Solved 2018 Set 2
CBSE Class 12 Biology Compartment Question Paper Solved 2018 Set 3
2017
CBSE Class 12 Biology Question Paper All India with Answers 2017 (1)
CBSE Class 12 Biology Question Paper All India with Answers 2017 (2)
CBSE Class 12 Biology Question Paper All India with Answers 2017 (3)
CBSE Class 12 Biology Question Paper Delhi with Answers 2017 (1)
CBSE Class 12 Biology Question Paper Delhi with Answers 2017 (3)
CBSE Class 12 Biology Question Paper Foreign with Answers 2017 (1)
CBSE Class 12 Biology Question Paper Foreign with Answers 2017 (2)
CBSE Class 12 Biology Question Paper Foreign with Answers 2017 (3)
2016
CBSE Class 12 Biology Question Paper 2016 Set 1
CBSE Class 12 Biology Question Paper 2016 Set 1 Delhi
CBSE Class 12 Biology Question Paper 2016 Set 1 Foreign
CBSE Class 12 Biology Question Paper 2016 Set 2
CBSE Class 12 Biology Question Paper 2016 Set 2 Delhi
CBSE Class 12 Biology Question Paper 2016 Set 2 Foreign
CBSE Class 12 Biology Question Paper 2016 Set 3
CBSE Class 12 Biology Question Paper 2016 Set 3 Delhi
CBSE Class 12 Biology Question Paper 2016 Set 3 Foreign
2015
CBSE Class 12 Biology Question Paper 2015 (Delhi Set 1) with Answers (Compartment)
CBSE Class 12 Biology Question Paper 2015 (Delhi Set 2) with Answers (Compartment)
CBSE Class 12 Biology Question Paper 2015 (Delhi Set 3) with Answers (Compartment)
CBSE Class 12 Biology Question Paper 2015 (Outside Delhi Set 1) with Answers (Compartment)
CBSE Class 12 Biology Question Paper 2015 (Outside Delhi Set 2) with Answers (Compartment)
CBSE Class 12 Biology Question Paper 2015 (Outside Delhi Set 3) with Answers (Compartment)
CBSE Class 12 Biology Question Paper 2015 Delhi Set 1 with Answers (Reval)
CBSE Class 12 Biology Question Paper 2015 Delhi Set 2 with Answers (Reval)
CBSE Class 12 Biology Question Paper 2015 Delhi Set 3 with Answers (Reval)
CBSE Class 12 Biology Question Paper 2015 Foreign Set 1 with Answers (Reval)
CBSE Class 12 Biology Question Paper 2015 Foreign Set 2 with Answers (Reval)
CBSE Class 12 Biology Question Paper 2015 Foreign Set 3 with Answers (Reval)
CBSE Class 12 Biology Question Paper 2015 Outside Delhi Set 1 with Answers (Reval)
CBSE Class 12 Biology Question Paper 2015 Outside Delhi Set 2 with Answers (Reval)
CBSE Class 12 Biology Question Paper 2015 Outside Delhi Set 3 with Answers (Reval)
2014
CBSE Class 12 Biology Question Paper 2014 Set 1 - Delhi
CBSE Class 12 Biology Question Paper 2014 Set 1 - Foreign
CBSE Class 12 Biology Question Paper 2014 Set 1 - Outside Delhi
CBSE Class 12 Biology Question Paper 2014 Set 2 - Delhi
CBSE Class 12 Biology Question Paper 2014 Set 2 - Foreign
CBSE Class 12 Biology Question Paper 2014 Set 2 - Outside Delhi
CBSE Class 12 Biology Question Paper 2014 Set 3 - Delhi
CBSE Class 12 Biology Question Paper 2014 Set 3 - Foreign
CBSE Class 12 Biology Question Paper 2014 Set 3 - Outside Delhi
CBSE Class 12 Biology Question Paper SA1 2014
CBSE Class 12 Biology Question Paper SA2 2014 (1)
CBSE Class 12 Biology Question Paper SA2 2014 (2)
CBSE Class 12 Biology Question Paper SA2 2014 (3)
2013
CBSE Class 12 Biology Question Paper 2013 (1)
CBSE Class 12 Biology Question Paper 2013 (2)
CBSE Class 12 Biology Question paper 2013 (3)
CBSE Class 12 Biology Question Paper 2013 (4)
CBSE Class 12 Biology Question Paper SA1 2013
CBSE Class 12 Biology Question Paper SA2 2013
CBSE Class 12 Biology Question Papers Delhi 2013 (1)
CBSE Class 12 Biology Question Papers Delhi 2013 (2)
CBSE Class 12 Biology Question Papers Delhi 2013 (3)
CBSE Class 12 Biology Question Papers Delhi 2013 (4)
CBSE Class 12 Biology Question Papers Foriegn 2013 (1)
CBSE Class 12 Biology Question Papers Foriegn 2013 (2)
CBSE Class 12 Biology Question Papers Outside Delhi 2013 (1)
CBSE Class 12 Biology Question Papers Outside Delhi 2013 (2)
CBSE Class 12 Biology Question Papers Outside Delhi 2013 (3)
CBSE Class 12 Biology Sample Papers 2013 (16)
2012
CBSE Class 12 Biology Question Paper 2012 (1)
CBSE Class 12 Biology Question paper 2012 (2)
CBSE Class 12 Biology Question paper 2012 (3)
CBSE Class 12 Biology Question paper 2012 (4)
2011
CBSE Class 12 Biology Question Papers SA1 2011 (1)
CBSE Class 12 Biology Question Papers SA1 2011 (2)
2010
CBSE Class 12 Biology Question Papers SA1 2010 (1)
2009
CBSE Class 12 Biology Question Paper 2009 (1)
CBSE Class 12 Biology Question Paper 2009 (2)
CBSE Class 12 Biology Question Paper 2009 (3)
CBSE Class 12 Biology Question Paper 2009 (4)
2008
CBSE Class 12 Biology Question Paper 2008 (1)
CBSE Class 12 Biology Question Paper 2008 (2)
CBSE Class 12 Biology Question Paper 2008 (3)
CBSE Class 12 Biology Question Paper 2008 (4)
CBSE Class 12 Biology Question Paper 2008 (5)
CBSE Class 12 Biology Question Paper 2008 (6)
CBSE Class 12 Biology Question Paper 2008 (7)
CBSE Class 12 Biology Question Paper 2008 Answers
CBSE Class 12 Biology Question Paper 2008 Answers(2)
2007
CBSE Class 12 Biology Question Paper 2007 (1)
CBSE Class 12 Biology Question Paper 2007 (2)
CBSE Class 12 Biology Question Paper 2007 (3)
2006
CBSE Class 12 Biology Question Paper 2006 (1)
CBSE Class 12 Biology Question Paper 2006 (2)
CBSE Class 12 Biology Question Paper 2006 (3)
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CBSE Class XII Biology Question Paper 1
CBSE Class XII Biology Question Paper 1 (For Blind Candidates)
CBSE Class XII Biology Question Paper 2
CBSE Class XII Biology Question Paper 3
CBSE Class XII Biotechnology Question Paper 1

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CBSE Class 12 Biology Question Paper 2021 Set A Solved

To understand the types of questions asked in past examinations, it is very important for Class 12 students to solve the CBSE Class 12 Biology Question Paper 2021 Set A Solved provided above. You can easily download these past papers for Class 12 Biology in PDF format for the last 10 years. By practicing these actual exam questions you will gain an understanding of the difficulty level and the variety of topics covered over the years. By solving these Previous Year Papers (PYPs) you will understand both descriptive and MCQ questions in your final tests.

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Regularly practicing CBSE Class 12 Biology Question Paper 2021 Set A Solved is the best way to improve your score in Class 12 Biology. These papers will give you details of the marking scheme and the paper structure used by the CBSE. By regularly attempting these under actual exam conditions at home, you can slowly improve your time management skills, which will help you to complete your Biology paper within the allowed duration.

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Having the CBSE Class 12 Biology Question Paper 2021 Set A Solved in PDF format allows you to revise key concepts anywhere, even without an internet connection. These sets are a reliable tool to practice numerical problems and understand the correct approach to all types of answers. After solving the questions, you should compare your work with the solutions provided by our teachers. Along with these papers, students should always solve the Class 12 Biology Sample Papers and MCQ tests on studiestoday.com for a complete revision.

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Yes, the solutions for CBSE Class 12 Biology Question Paper 2021 Set A Solved are prepared by subject matter experts as per official marking scheme. Class 12 students will understand the structure of answers and 'step-marks' methodology Biology.

How does solving CBSE Class 12 Biology Question Paper 2021 Set A Solved help in preparing for the 2026 exams?

Solving previous year papers like CBSE Class 12 Biology Question Paper 2021 Set A Solved is important to understand repeat themes and question difficulty levels of Biology. It helps Class 12 students to test their time management skills too.

Can I access CBSE Class 12 Biology Question Paper 2021 Set A Solved in different languages?

Yes, where applicable, CBSE Class 12 Biology Question Paper 2021 Set A Solved is available in both English and Hindi mediums. All students from Class 12 can access Biology study material in their preferred language.

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