CBSE Class 12 Biology 2026 question paper (57/3)

1. A.
   Oxytocin from foetal pituitary gland
2. B.
   hCG from placenta
3. C.
   Progesterone from corpus luteum
4. D.
   Oxytocin from maternal pituitary gland

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1. A.
   Energy flow
2. B.
   Decomposition
3. C.
   Stratification
4. D.
   Productivity

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1. A.
   a-iii, b-i, c-iv, d-ii
2. B.
   a-iii, b-i, c-ii, d-iv
3. C.
   a-i, b-iii, c-iv, d-ii
4. D.
   a-i, b-iv, c-ii, d-iii

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1. A.
   Producing petrol-like fuel
2. B.
   Reduction of Vitamin A deficiency in humans
3. C.
   Pest resistance
4. D.
   Herbicide tolerance

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1. A.
   Terminator box at left, Promoter box at right; top strand 3' (left) to 5' (right), TACGACTACGCT, labelled Template strand; bottom strand 5' (left) to 3' (right), ATGCTGATGCGA, labelled Coding strand
2. B.
   Promoter box at left, Terminator box at right; top strand 5' (left) to 3' (right), TACGACTACGCT, labelled Template strand; bottom strand 3' (left) to 5' (right), ATGCTGATGCGA, labelled Coding strand
3. C.
   Promoter box at left, Terminator box at right; top strand 3' (left) to 5' (right), TACGACTACGCT, labelled Template strand; bottom strand 5' (left) to 3' (right), ATGCTGATGCGA, labelled Coding strand
4. D.
   Promoter box at left, Terminator box at right; top strand 3' (left) to 5' (right), TACGACTACGCT, labelled Coding strand; bottom strand 5' (left) to 3' (right), ATGCTGATGCGA, labelled Template strand

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1. A.
   Adaptive radiation
2. B.
   Divergent evolution
3. C.
   Artificial selection
4. D.
   Anthropogenic action

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1. A.
   (i), (ii), (iv) and (v) are correct
2. B.
   (ii), (iii) and (iv) are correct
3. C.
   All are correct
4. D.
   Only (i) and (iv) are correct

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1. A.
   Intestinal blockage
2. B.
   Muscular pain and fever
3. C.
   Anaemia
4. D.
   Skin ulcers

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1. A.
   Standing crop
2. B.
   Primary productivity
3. C.
   Standing state
4. D.
   Ecological efficiency

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1. A.
   Oligonucleotide
2. B.
   Codon
3. C.
   Gene
4. D.
   Nucleotide

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1. A.
   Statements (i), (iv) and (v) are correct
2. B.
   Statements (i), (ii) and (iii) are correct
3. C.
   Only statements (i) and (v) are correct
4. D.
   Only statement (iii) is correct

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1. A.
   Vallisneria and Hydrilla
2. B.
   Zostera and Water lily
3. C.
   Water lily and Parthenium
4. D.
   Water hyacinth and Water lily

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Funicle
2. B.
   Chalaza
3. C.
   Nucellus
4. D.
   Integuments

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1. A.
   Statements (i), (iv) and (v) are correct
2. B.
   Statements (i), (ii) and (iii) are correct
3. C.
   Only statements (i) and (v) are correct
4. D.
   Only statement (iii) is correct

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1. A.
   Adaptive radiation
2. B.
   Divergent evolution
3. C.
   Artificial selection
4. D.
   Anthropogenic action

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1. A.
   Both Statements I and II are false.
2. B.
   Both Statements I and II are true.
3. C.
   Only Statement I is true.
4. D.
   Only Statement II is true.

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1. A.
   Garden pea
2. B.
   Escherichia coli
3. C.
   Vicia faba
4. D.
   Drosophila

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1. A.
   Energy flow
2. B.
   Decomposition
3. C.
   Stratification
4. D.
   Productivity

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1. A.
   Producing petrol-like fuel
2. B.
   Reduction of Vitamin A deficiency in humans
3. C.
   Pest resistance
4. D.
   Herbicide tolerance

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1. A.
   Macrophages
2. B.
   Helper T-Lymphocytes
3. C.
   Cytotoxic T-Cells
4. D.
   B-Lymphocytes

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1. A.
   Grasshopper
2. B.
   Cow
3. C.
   Fish
4. D.
   Hawk

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1. A.
   a-iii, b-i, c-iv, d-ii
2. B.
   a-iii, b-i, c-ii, d-iv
3. C.
   a-i, b-iii, c-iv, d-ii
4. D.
   a-i, b-iv, c-ii, d-iii

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1. A.
   (i), (ii), (iv) and (v) are correct
2. B.
   (ii), (iii) and (iv) are correct
3. C.
   All are correct
4. D.
   Only (i) and (iv) are correct

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1. A.
   Oral Pills
2. B.
   Copper-T
3. C.
   Condom
4. D.
   Lippes loop

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   (i) 800; (ii) $1{\cdot}6$ million
2. B.
   (i) 300; (ii) 2400
3. C.
   (i) 8000; (ii) $1{\cdot}2$ million
4. D.
   (i) 3000; (ii) $2{\cdot}4$ million

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1. A.
   Culex mosquito
2. B.
   Female Anopheles mosquito
3. C.
   Snail
4. D.
   Housefly

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1. A.
   It cuts after the first nucleotide in the restriction site.
2. B.
   It is the first enzyme isolated from strain $\text{S}_2$ of bacterium.
3. C.
   Only one enzyme can be used to digest a plasmid from $\text{S}_2$ strain.
4. D.
   Only one restriction enzyme has been isolated from this bacteria.

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1. A.
   Vallisneria and Hydrilla
2. B.
   Zostera and Water lily
3. C.
   Water lily and Parthenium
4. D.
   Water hyacinth and Water lily

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1. A.
   Statements (i), (iv) and (v) are correct
2. B.
   Statements (i), (ii) and (iii) are correct
3. C.
   Only statements (i) and (v) are correct
4. D.
   Only statement (iii) is correct

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1. A.
   25%
2. B.
   50%
3. C.
   75%
4. D.
   100%

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1. A.
   Terminator box at left, Promoter box at right; top strand 3' (left) to 5' (right), TACGACTACGCT, labelled Template strand; bottom strand 5' (left) to 3' (right), ATGCTGATGCGA, labelled Coding strand
2. B.
   Promoter box at left, Terminator box at right; top strand 5' (left) to 3' (right), TACGACTACGCT, labelled Template strand; bottom strand 3' (left) to 5' (right), ATGCTGATGCGA, labelled Coding strand
3. C.
   Promoter box at left, Terminator box at right; top strand 3' (left) to 5' (right), TACGACTACGCT, labelled Template strand; bottom strand 5' (left) to 3' (right), ATGCTGATGCGA, labelled Coding strand
4. D.
   Promoter box at left, Terminator box at right; top strand 3' (left) to 5' (right), TACGACTACGCT, labelled Coding strand; bottom strand 5' (left) to 3' (right), ATGCTGATGCGA, labelled Template strand

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1. A.
   Oxytocin from foetal pituitary gland
2. B.
   hCG from placenta
3. C.
   Progesterone from corpus luteum
4. D.
   Oxytocin from maternal pituitary gland

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1. A.
   a-i, b-ii, c-iii, d-iv
2. B.
   a-ii, b-iii, c-iv, d-i
3. C.
   a-ii, b-iv, c-i, d-iii
4. D.
   a-ii, b-i, c-iv, d-iii

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1. A.
   Pseudogene
2. B.
   Structural gene
3. C.
   Split gene
4. D.
   Oncogene

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1. A.
   Producing petrol-like fuel
2. B.
   Reduction of Vitamin A deficiency in humans
3. C.
   Pest resistance
4. D.
   Herbicide tolerance

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1. A.
   Intestinal blockage
2. B.
   Muscular pain and fever
3. C.
   Anaemia
4. D.
   Skin ulcers

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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1. A.
   Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
2. B.
   Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
3. C.
   Assertion (A) is true, but Reason (R) is false.
4. D.
   Assertion (A) is false, but Reason (R) is true.

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