Question

How do guard cells control the opening and closing of stomata

Answer 1

Guard cell opens when plant needs CO2 and sunlight for making food. And when they take it they close. In this way they control opening and closing of stomata. Please comment on this answer hope this will help you

Answer 2

The opening and closing of the pore is a function of the guard cells. The guard cells swell when water flows into them, causing the stomatal pore to open. Simillarly the pore closes if the guard cells shrink