CBSE Class 12 Biology Boards 2020 Question Paper Set 04 Solved

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Class 12 Biology Solved Question Papers: CBSE Class 12 Biology Boards 2020 Question Paper Set 04 Solved

Explore authentic exam materials through the CBSE Class 12 Biology Boards 2020 Question Paper Set 04 Solved. Tailored for Class 12 learners, utilizing these Biology previous year papers ensures thorough preparation and strengthens time management skills before final CBSE evaluations.

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View or download the dedicated CBSE Class 12 Biology Boards 2020 Question Paper Set 04 Solved resource below. Engaging with these previous year papers under timed conditions ensures continuous academic progress and mastery of the 2026-27 exam format.

SECTION – A
1. Which one of the following is not found in a female gametophyte of an angiosperm ?
 
(a) Germ pore
 
(b) Synergids
 
(c) Filiform apparatus
 
(d) Central cell
 
2. The autosomal disorder/disease in humans is
 
(a) Colour blindness
 
(b) Thalassemia
 
(c) Haemophilia
 
(d) Turner’s Syndrome
 
3. Choose the chromosome, in a human, that possesses least number of genes.
 
(a) 21st Chromosome
 
(b) Autosome
 
(c) X-Chromosome
 
(d) Y-Chromosome
 
4. The practice of mating unrelated animals within the same breed, but with no common ancestor on either side of the pedigree for 4-6 generation is known as
 
(a) out-breeding
 
(b) out-crossing
 
(c) cross-breeding
 
(d) in-breeding 
            OR
Bacteria present in rumen of a cattle digest cellulose to produce
 
(a) Polysaccharides
 
(b) Sucrose
 
(c) Ethanol
 
(d) Methane 
 
5. It is observed that, the species diversity decreases as we
 
(a) move away from equator to poles
 
(b) move towards equator from poles
 
(c) move along the equator
 
(d) move from deserts to rain-forests. 
                        OR
CNG is preferred as a fuel over diesel for public transport because
 
(i) it is cost effective.
 
(ii) it burns almost completely.
 
(iii) it can be recycled.
 
(iv) it burns only partially.
 
Choose the correct combination.
 
(a) (i) + (ii)
 
(b) (i) + (iii)
 
(c) (ii) + (iii)
 
(d) (iii) + (iv) 
 
SECTION – B
6. Mention the advantages of emasculation and bagging in artificial hybridization in plants bearing unsexual, and bisexual flowers.
 
7. Two children one with blood group ‘AB’ and other with blood group ‘O’ are born to parents, where the father has blood group ‘A’ and the mother has blood group ‘B’. Work out a cross to show how is it possible ? 
 
8. Name the types of acquired immune responses, and the special types of lymphocytes involved in providing them.
OR
Name two organisms belonging to two different kingdoms, that are commonly used as biofertilizers, and how ? 
 
9. Write the basis of naming the restriction endonuclease EcoR-I. 
 
10. What are transgenic animals ? How was the first transgenic cow found to be more useful than the normal cow, for humans ?
 
11. How do the following organisms pull through the adverse environmental conditions ?
 
(a) Fungi
 
(b) Zooplankton
 
(c) Bear
 
(d) Snails 
 
12. (a) How many primary producers do you think would be needed to support six tertiary consumers in a grassland ecosystem ?
 
     (b) Draw a grassland pyramid to substantiate your answer.
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Where can I download the official PDF for CBSE Class 12 Biology Boards 2020 Question Paper Set 04 Solved?

The CBSE Class 12 Biology Boards 2020 Question Paper Set 04 Solved is available for download on StudiesToday.com. It includes complete set with all sections so that Class 12 students can practice with the exact same paper that came in the CBSE exams.

Are the solutions for CBSE Class 12 Biology Boards 2020 Question Paper Set 04 Solved based on the official CBSE marking scheme?

Yes, the solutions for CBSE Class 12 Biology Boards 2020 Question Paper Set 04 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 Boards 2020 Question Paper Set 04 Solved help in preparing for the 2026 exams?

Solving previous year papers like CBSE Class 12 Biology Boards 2020 Question Paper Set 04 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 Boards 2020 Question Paper Set 04 Solved in different languages?

Yes, where applicable, CBSE Class 12 Biology Boards 2020 Question Paper Set 04 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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No, all previous year question papers on StudiesToday, including CBSE Class 12 Biology Boards 2020 Question Paper Set 04 Solved, are provided free of charge in mobile-friendly PDF.