Question

At what time of day would stomata be closed and why

Answer 1

in general, they open during the day and close at night.

Step-by-step explanation:

during the day, photosynthesis requires it to be open to get CO2, and at night it needs to be closed to avoid losing water

Answer 2

The stomata closes down at night when there is no sun and there's no photosynthesis. It also closes down when the air is dry and when it's hot so as to prevent excessive loss of water.