Image Caption
Carbon dioxide enters, while water and oxygen exit, through a leaf's stomata. Stomata control a tradeoff for the plant: they allow carbon dioxide in, but they also let precious water escape.
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Stomata (2 of 3) Tradeoff
Levels of carbon dioxide in Earth's atmosphere change over time; so at times when the atmosphere is carbon-dioxide-rich, plants can get away with having fewer stomata since each individual stoma…![](https://evolution.berkeley.edu/wp-content/uploads/2021/10/33615_evo_resources_resource_image_372_original-350x350.gif)