# Gas Exchange & Breathing

Describe the structure of the human gas exchange system (trachea, bronchi, bronchioles, alveoli) and explain how the mechanism of breathing — using pressure changes from rib and diaphragm movement — moves air in and out of the lungs

Builds on: Cells to Organ Systems (soft, https://ai.page/c/cells-to-organ-systems/en.md), How Diffusion Works (hard, https://ai.page/c/how-diffusion-works/en.md)

Concept id: gas-exchange-and-breathing. Subject: science. Licence: CC BY-SA 4.0.

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