Hello there, friend! A simple answer is below.
The answer is Guard Cell.
Step-by-step explanation:
Guard cells are specialized plant cells that regulate gas exchange in the epidermis of leaves, stems, and other organs. They are generated in pairs, with a stomatal hole forming the space between them. When water is abundant and the guard cells are turgid, the stomatal holes are the biggest; when water is scarce and the guard cells become flaccid, the stomatal apertures close.