The small hole through which water and gases pass in and out of a plant is called a stoma.

Here's why:

* Stomata (plural of stoma) are tiny pores on the surface of leaves and stems.

* Gas Exchange: They allow the plant to take in carbon dioxide for photosynthesis and release oxygen as a byproduct.

* Transpiration: Stomata also help regulate the plant's water content by releasing water vapor into the atmosphere.

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