Answer: When the plant has enough water in its cells the guard cells swell up and open the stomata. When the plant isn't getting enough water the guard cells can't swell and the stomata stay closed, so the plant doen's lose water. But if the stomata are closed photosynthesis can't happen and eventually the plant might starve.
Explanation:
Both require oxygen. hope this helped! have a good day:)
Eliptical (oval shaped), rather than Circular.
