Question

how do the opening and closing of stomata control the rate of transpiration

Answer 1

the opening and the closing of stomata controlthe rate of transpiration as it means the evaporation of water from the leaves so when it close and opens it only lets some water to be evaporated as because if too much water will be evaporated then the plant would die

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