# The circulatory system is an example of an organ system in the human body. Explain why the circulatory system is described as an organ system rather than an organ.

> Pearson Edexcel International GCSE Biology (4BI1) — 2.1 Levels of organisation · Explain · 4 marks

> The circulatory system includes the heart, blood vessels and blood, all working together to transport substances around the body.

## Mark scheme (4 marks)

1. An organ is an aggregation of tissues performing a specific function
2. An organ system is a group of organs that work together
3. The circulatory system contains more than one organ, e.g. the heart and blood vessels
4. These organs work together to carry out the overall function of transporting substances around the body

## Key terms

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

## 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)
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Source: [GradeNine](https://www.gradenine.co.uk/q/the-circulatory-system-is-an-example-4738cfcf) · Published by Druglandscape Ltd.