AP BIOLOGY

Detailed explanation-1: -Guard cells use osmotic pressure to open and close stomata, allowing plants to regulate the amount of water and solutes within them.

Detailed explanation-2: -Upon the incoming of water inside the guard cells, they swell up to become like a curved banana surface, due to which the stomatal pore opens up. When the guard cells lose water, they become flaccid and straight and thus, close the stomatal aperture. Guard cells and stomata regulates the respiration process in plants.

Detailed explanation-3: -When the two guard cells are turgid (swollen with water), the stoma is open, and, when the two guard cells are flaccid, it is closed.

Detailed explanation-4: -Guard cells have a special structure that helps them to open and close. The aim of the process is to control the amount of water getting outside the plant in case of water stress.