# Explain how sexual reproduction in animals results in offspring that are genetically different from their parents.

> Edexcel A-Level Biology A: Salters-Nuffield (9BN0) — 2.3 Sexual reproduction in animals and plants · Explain · 5 marks

> Sexual reproduction in animals involves the production of gametes by meiosis and their fusion during fertilisation.

## Mark scheme (5 marks)

1. Gametes are haploid / contain a single copy of each chromosome
2. Meiosis produces gametes with different combinations of chromosomes / genetic variation is introduced during meiosis
3. Fertilisation is the fusion of a male and female gamete
4. Fertilisation restores the diploid number / the fertilised egg contains two copies of each chromosome
5. The offspring inherit a unique combination of chromosomes / genes from both parents, resulting in genetic variation

## Related

- [Revision notes for Edexcel A-Level Biology A: Salters-Nuffield (9BN0)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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