What are the tiny pores in the epidermis of a leaf that allow gas exchange called?

The tiny pores in the epidermis of a leaf that facilitate gas exchange are known as stomata. These specialized openings play a crucial role in the process of photosynthesis and respiration. They allow carbon dioxide to enter the leaf for photosynthesis while enabling oxygen, a byproduct of this process, to exit. Additionally, stomata help regulate water loss through transpiration, which is crucial for maintaining the plant's internal water balance.

In contrast, trichomes are hair-like structures that can serve various functions such as reducing water loss and deterring herbivores, while cuticles are the waxy layers that cover the leaf surface to minimize water loss. Chloroplasts, on the other hand, are the organelles responsible for photosynthesis; they are not involved in gas exchange but are found within the cells of the leaf. Thus, stomata are essential for the gas exchange process in plants, making them the correct choice for this question.