Q1. [1] deep exam-ready
Assertion (A): In sexual reproduction, each new generation does not end up with twice the DNA content of the previous generation.
Reason (R): Germ-cells are produced by a specialised division that halves the chromosome number, so that when two germ-cells fuse, the original chromosome number is restored.
- A Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- B Both Assertion (A) and Reason (R) are true, but Reason (R) is NOT the correct explanation of Assertion (A).
- C Assertion (A) is true, but Reason (R) is false.
- D Assertion (A) is false, but Reason (R) is true.
Generated by claude-sonnet-4-6 · 2026-06-26 01:01 · grounding rag
Model Answer
Option A is correct. Both A and R are true, and R is the correct explanation of A. Germ-cells formed by meiosis carry half the chromosome number; fusion of two germ-cells restores the original number, preventing DNA doubling each generation.
Source: Chapter 7, Section 7.3.1
Explanation
- The passage explicitly states the problem (doubling of DNA) and its solution (meiosis halving chromosomes in germ-cells, restored at fertilisation).
- Assertion is true — new generation does NOT double in DNA content.
- Reason correctly explains the mechanism (meiosis → half chromosomes → fusion restores full number), making it the correct explanation of the Assertion → Option A.