Science (086) — AI-generated practice question

During sexual reproduction, two germ-cells (gametes) fuse at fertilisation to form a new individual. If each germ-cell contained the full chromosome number (as in normal body cells), the fertilised egg would have double the chromosomes. Across generations, this would keep doubling, disrupting the species' chromosome number entirely.

Meiosis halves the chromosome number in germ-cells so that after fertilisation, the normal chromosome number is restored in the offspring.

If germ-cells were produced by mitosis instead, they would carry the full chromosome number. Fusion of two such cells would double the chromosomes each generation, making it impossible to maintain a stable chromosome number across generations.

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Source: Chapter 7 — Reproduction, general principles of sexual reproduction and DNA/chromosome inheritance.

• The examiner wants two linked ideas: (1) why halving is necessary (fertilisation doubles), and (2) what goes wrong without meiosis (chromosomes keep doubling each generation).
• Use terms like meiosis, fertilisation, chromosome number, gametes — these earn keyword marks.
• At 3 marks, roughly one mark per idea: (i) fertilisation combines two gametes, (ii) meiosis keeps the count stable, (iii) mitosis-produced gametes would cause progressive doubling. Cover all three concisely.