# Describe the role of decomposers in the carbon cycle.

> Pearson Edexcel International GCSE Biology (4BI1) — 4.3 Cycles within ecosystems · Describe · 4 marks

> Dead leaves and animal remains accumulate on a forest floor. Over time, these materials disappear and carbon dioxide is released back into the atmosphere.

## Mark scheme (4 marks)

1. Decomposers release enzymes that break down dead plant and animal material
2. Decomposers carry out respiration, releasing carbon dioxide into the atmosphere
3. This returns carbon (as carbon dioxide) from dead organic matter to the atmosphere
4. The rate of decomposition is affected by temperature, water availability or oxygen availability

## Key terms

- [decomposers](https://www.gradenine.co.uk/glossary/decomposers)
- [carbon cycle](https://www.gradenine.co.uk/glossary/carbon-cycle)

## Related

- [Revision notes for Pearson Edexcel International GCSE Biology (4BI1)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-the-role-of-decomposers-in-3a4ef1ba) · Published by Druglandscape Ltd.