CBSE Class 12 Biology 2023 question paper (57/1)

1. A.
   (iv) only
2. B.
   (ii) and (iv)
3. C.
   (i), (ii) and (iii)
4. D.
   (i), (ii), (iii) and (iv)

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1. A.
   Terminator, Sigma ($\sigma$), RNA polymerase
2. B.
   Promoter, Rho ($\rho$), RNA polymerase
3. C.
   Promoter, Sigma ($\sigma$), RNA polymerase
4. D.
   Promoter, Sigma ($\sigma$), DNA polymerase

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1. A.
   Declining population
2. B.
   Stable population
3. C.
   Expanding population
4. D.
   Extinct population

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1. A.
   Point (i)
2. B.
   Point (ii)
3. C.
   Point (iii)
4. D.
   Point (iv)

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1. A.
   P-i, Q-ii, R-iv, S-iii
2. B.
   P-iv, Q-iii, R-ii, S-i
3. C.
   P-i, Q-iv, R-iii, S-ii
4. D.
   P-iii, Q-i, R-ii, S-iv

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1. A.
   1 and 2
2. B.
   2 and 3
3. C.
   1 and 3
4. D.
   Only individual 3

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1. A.
   Stabilising selection as giraffes with longer neck lengths are selected further.
2. B.
   Disruptive selection as giraffes with smaller and longer neck lengths are selected.
3. C.
   Directional selection as giraffes with longer neck lengths are selected.
4. D.
   Stabilising selection as giraffes with medium neck lengths are selected.

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1. A.
   325
2. B.
   650
3. C.
   1300
4. D.
   975

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1. A.
   P-ii, Q-iv, R-iii, S-i
2. B.
   P-i, Q-ii, R-iii, S-iv
3. C.
   P-iii, Q-i, R-iv, S-ii
4. D.
   P-iv, Q-iii, R-ii, S-i

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1. A.
   Sertoli cells, Testosterone, Development of secondary sexual characteristics
2. B.
   Placenta, Estrogen, Initiates secretion of milk
3. C.
   Leydig cells, Androgen, Initiates the production of sperms
4. D.
   Ovary, FSH, Stimulates follicular development

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1. A.
   E. coli
2. B.
   Salmonella typhimurium
3. C.
   Agrobacterium tumefaciens
4. D.
   Bacillus thuringiensis

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1. A.
   Mr. Ajay Phadke
2. B.
   Ms. Vandana Shiva
3. C.
   Dr. Venugopalan
4. D.
   Dr. R.A. Mashelkar

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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.
   R – T – S
2. B.
   R – S – T
3. C.
   S – R – T
4. D.
   S – T – R

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1. A.
   Point (i)
2. B.
   Point (ii)
3. C.
   Point (iii)
4. D.
   Point (iv)

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1. A.
   Terminator, Sigma ($\sigma$), RNA polymerase
2. B.
   Promoter, Rho ($\rho$), RNA polymerase
3. C.
   Promoter, Sigma ($\sigma$), RNA polymerase
4. D.
   Promoter, Sigma ($\sigma$), DNA polymerase

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1. A.
   Declining population
2. B.
   Stable population
3. C.
   Expanding population
4. D.
   Extinct population

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1. A.
   $\alpha$-1-antitrypsin
2. B.
   $\alpha$-lactalbumin
3. C.
   $\beta$-lactglucose
4. D.
   $\alpha$-deaminase

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1. A.
   Stabilising selection as giraffes with longer neck lengths are selected further.
2. B.
   Disruptive selection as giraffes with smaller and longer neck lengths are selected.
3. C.
   Directional selection as giraffes with longer neck lengths are selected.
4. D.
   Stabilising selection as giraffes with medium neck lengths are selected.

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1. A.
   1 and 2
2. B.
   2 and 3
3. C.
   1 and 3
4. D.
   Only individual 3

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1. A.
   325
2. B.
   650
3. C.
   1300
4. D.
   975

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1. A.
   (i) $\rightarrow$ (iii) $\rightarrow$ (iv) $\rightarrow$ (ii) $\rightarrow$ (v)
2. B.
   (i) $\rightarrow$ (iv) $\rightarrow$ (ii) $\rightarrow$ (iii) $\rightarrow$ (v)
3. C.
   (ii) $\rightarrow$ (i) $\rightarrow$ (iii) $\rightarrow$ (iv) $\rightarrow$ (v)
4. D.
   (ii) $\rightarrow$ (iv) $\rightarrow$ (v) $\rightarrow$ (iii) $\rightarrow$ (i)

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1. A.
   (ii) $\rightarrow$ (iii) $\rightarrow$ (i) $\rightarrow$ (iv)
2. B.
   (iii) $\rightarrow$ (ii) $\rightarrow$ (i) $\rightarrow$ (iv)
3. C.
   (iii) $\rightarrow$ (i) $\rightarrow$ (ii) $\rightarrow$ (iv)
4. D.
   (i) $\rightarrow$ (iii) $\rightarrow$ (iv) $\rightarrow$ (ii)

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1. A.
   Progesterone
2. B.
   Estrogen
3. C.
   Human Chorionic Gonadotropin (HCG)
4. D.
   Relaxin

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1. A.
   Genital herpes
2. B.
   Gonorrhoea
3. C.
   Genital warts
4. D.
   Hepatitis-B

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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.
   at the time of fertilisation
2. B.
   when the sperm touches the zona pellucida
3. C.
   when the sperm gains entry into the cytoplasm of the ovum
4. D.
   when the acrosome of the sperm releases its enzymes on corona radiata

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1. A.
   325
2. B.
   650
3. C.
   1300
4. D.
   975

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1. A.
   P-ii, Q-iv, R-iii, S-i
2. B.
   P-i, Q-ii, R-iii, S-iv
3. C.
   P-iii, Q-i, R-iv, S-ii
4. D.
   P-iv, Q-iii, R-ii, S-i

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1. A.
   Wheat
2. B.
   Tobacco
3. C.
   Rice
4. D.
   Cotton

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1. A.
   Terminator, Sigma ($\sigma$), RNA polymerase
2. B.
   Promoter, Rho ($\rho$), RNA polymerase
3. C.
   Promoter, Sigma ($\sigma$), RNA polymerase
4. D.
   Promoter, Sigma ($\sigma$), DNA polymerase

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1. A.
   1 and 2
2. B.
   2 and 3
3. C.
   1 and 3
4. D.
   Only individual 3

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1. A.
   Stabilising selection as giraffes with longer neck lengths are selected further.
2. B.
   Disruptive selection as giraffes with smaller and longer neck lengths are selected.
3. C.
   Directional selection as giraffes with longer neck lengths are selected.
4. D.
   Stabilising selection as giraffes with medium neck lengths are selected.

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1. A.
   I, High temp. / $90^{\circ}\text{C}$, Heat stable
2. B.
   II, Low temp. / $50^{\circ}\text{C}$, Heat stable
3. C.
   III, Low temp. / $50^{\circ}\text{C}$, Heat resistant
4. D.
   IV, High temp. / $90^{\circ}\text{C}$, Heat unstable

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1. A.
   dsDNA
2. B.
   dsRNA
3. C.
   rDNA
4. D.
   DNA polymerase

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1. A.
   Oscillatoria
2. B.
   Rhizobium
3. C.
   Azospirillum
4. D.
   Glomus

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1. A.
   P-i, Q-ii, R-iv, S-iii
2. B.
   P-iv, Q-iii, R-ii, S-i
3. C.
   P-i, Q-iv, R-iii, S-ii
4. D.
   P-iii, Q-i, R-ii, S-iv

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1. A.
   (i) and (ii)
2. B.
   (i) and (iv)
3. C.
   (ii) and (iii)
4. D.
   (ii) and (iv)

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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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