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Science (086) — AI-generated practice question

AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.

Q1. [1] medium exam-ready
In sexually reproducing organisms, each germ cell carries only one copy of each gene. Why is this necessary? ((A)) So that the offspring receive double the number of chromosomes from each parent ((B)) So that fertilisation restores the full two copies of each gene in the offspring ((C)) So that mutations occur less frequently in germ cells than in body cells ((D)) So that both parents contribute genes of identical type to the offspring
  1. A So that offspring have half the DNA of their parents
  2. B So that when two germ cells combine, the normal chromosome number is restored in the offspring
  3. C To ensure only dominant traits are passed on
  4. D To prevent any variation from occurring in offspring
Generated by claude-sonnet-4-6 · 2026-06-26 01:02 · grounding rag
Model Answer

(B) So that when two germ cells combine, the normal chromosome number is restored in the offspring.

Germ cells are formed by meiosis, carrying only half the chromosomes. At fertilisation, two germ cells fuse, restoring the full chromosome number in the offspring.

Explanation

The passage (Chapter 7, Section 7.3.1) clearly states that germ cells have half the chromosomes (via meiosis), so that when they combine during sexual reproduction, the original chromosome number and DNA content are re-established. Option B directly reflects this. Options A, C, and D are either incorrect or unrelated to the reason given in the textbook. Examiners expect you to link meiosis → half chromosomes → fertilisation → full number restored.

Source: Chapter 7, Section 7.3.1 — Why the Sexual Mode of Reproduction?

Previous-year CBSE Grade 10 board exam questions, organised by subject and chapter, each with a model answer — free to read and print.