# Explain how carbon stored in the bodies of dead animals is returned to the atmosphere as carbon dioxide.

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

> When animals die, their bodies contain large amounts of carbon stored in organic compounds such as proteins and fats.

## Mark scheme (4 marks)

1. Decomposers / microorganisms / bacteria and fungi break down / digest the dead animal material
2. Decomposers release enzymes that catalyse the breakdown of organic compounds into simpler organic matter
3. Decomposers (and other organisms) respire the organic compounds / use them as a food source in respiration
4. Carbon dioxide is released into the atmosphere as a product of respiration

## Related

- [Revision notes for Pearson Edexcel International GCSE Biology (4BI1)](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)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-how-carbon-stored-in-the-20fb63b7) · Published by Druglandscape Ltd.