Why are a plant’s stomata generally open during the day and closed at night?
A. Stomata are generally open during the day because water pressure in the guard cells drops during the day and closed at night because the water pressure is high.
B. Stomata are generally open during the day to allow oxygen needed for cellular respiration to enter and closed at night because cellular respiration does not occur at night.
C. Stomata are generally open during the day to remove excess water from the plant and closed at night to keep oxygen from escaping.
D. Stomata are generally open during the day to allow carbon dioxide to enter the leaves when photosynthesis is possible and closed at night to prevent water loss.