Q1. [1] straightforward exam-ready
Assertion (A): Each body cell of a sexually reproducing organism has two copies of each chromosome.
Reason (R): One copy of each chromosome is inherited from the mother and one from the father through their respective germ cells.
- A Both A and R are true, and R is the correct explanation of A
- B Both A and R are true, but R is NOT the correct explanation of A
- C A is true but R is false
- D A is false but R is true
Generated by claude-sonnet-4-6 · 2026-06-26 01:03 · grounding rag
Model Answer
Answer: A
Both A and R are true, and R is the correct explanation of A. In sexual reproduction, germ cells (egg and sperm) each contribute one copy of each chromosome, so body cells have two copies — one maternal, one paternal.
Explanation
- A is true: Body cells of sexually reproducing organisms are diploid (two copies of each chromosome).
- R is true: One copy comes from the mother's egg cell and one from the father's sperm cell.
- R correctly explains A: The two-copy nature of body chromosomes is directly caused by the fusion of two germ cells during fertilisation, making R the correct explanation of A.
- Key phrase from the chapter: "Most human chromosomes have a maternal and a paternal copy" — this directly links R to A.