Consider statements about genetics: 1. The human genome contains 23 pairs of chromosomes. 2. Sex is determined by the Y chromosome. 3. All mutations are harmful. Which are correct? MCQ with Answer and Explanation

Consider statements about genetics: 1. The human genome contains 23 pairs of chromosomes. 2. Sex is determined by the Y chromosome. 3. All mutations are harmful. Which are correct?
A. 1 and 2 only
B. 1 and 3 only
C. 1, 2 and 3
D. 2 and 3 only
Answer: Option A
Solution (By JKExamLibrary)
Human somatic cells are diploid, containing 23 pairs of chromosomes (22 pairs of autosomes and 1 pair of sex chromosomes). The presence of the Y chromosome determines male sex (XY), while its absence results in female sex (XX). Mutations are random changes in DNA; while some are harmful, many are neutral, and some can be beneficial, providing the genetic variation necessary for evolution. Thus, statements 1 and 2 are correct.

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Which of the following animals belongs to the class Chondrichthyes?
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Explanation:
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Correct Answer: Option D


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