# A compost heap contains dead plant material, food scraps and animal waste. Explain why the rate of decomposition in a compost heap is much faster in warm, moist conditions than in cold, dry conditions.

> Edexcel A-Level Biology A: Salters-Nuffield (9BN0) — 5.5 Decomposition and decay · Explain · 5 marks

> Gardeners often add water to their compost heaps and position them in sunny spots to speed up the breakdown of organic material.

## Mark scheme (5 marks)

1. Decomposers (bacteria / fungi) are responsible for breaking down the organic material
2. Decomposers use enzymes to break down organic material
3. Warmer temperatures increase the rate of enzyme activity, so decomposition is faster
4. Moist conditions allow decomposers to be more active / allow enzymes to function / allow diffusion of materials into and out of decomposers
5. In cold, dry conditions decomposer activity is reduced / enzymes are less active, so decomposition is slower

## Key terms

- [decomposition](https://www.gradenine.co.uk/glossary/decomposition)

## 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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Source: [GradeNine](https://www.gradenine.co.uk/q/a-compost-heap-contains-dead-plant-98beca8b) · Published by Druglandscape Ltd.