# Describe the path taken by an oxygen molecule from the nose to the alveoli.

> WJEC GCSE Biology (Wales) — 1.2.2 The respiratory system · Describe · 4 marks

## Mark scheme (4 marks)

1. Air passes through the trachea (windpipe)
2. The trachea divides / branches into two bronchi (one to each lung)
3. Bronchi divide into smaller bronchioles
4. Bronchioles lead to / end at the alveoli (air sacs) where gas exchange occurs

## Key terms

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

## Related

- [Revision notes for WJEC GCSE Biology (Wales)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" 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/describe-the-path-taken-by-an-0e81f36f) · Published by Druglandscape Ltd.