AP BIOLOGY

Detailed explanation-1: -Stomata are mouth-like cellular complexes at the epidermis that regulate gas transfer between plants and atmosphere. In leaves, they typically open during the day to favor CO2 diffusion when light is available for photosynthesis, and close at night to limit transpiration and save water.

Detailed explanation-2: -Stomata remain closed at night because of the following reasons: Plants lose the majority of their water through stomata. Thus, they close their stomata at night to prevent excess loss of water through them.

Detailed explanation-3: -Plants close stomata in response to their environment; for example, most plants close their stomata at night. Under drought, plants may also close their stomata to limit the amount of water that evaporates from their leaves.

Detailed explanation-4: -The stomatal openings remain closed at night as photosynthesis is not conducted without sunlight. They are closed to prevent water loss via the stomatal pores.

Detailed explanation-5: -Note: In succulent plants stomata close at night and open in day time because there is no sunlight at night for photosynthesis. CAM plants change carbon dioxide into malic acid during night. They do so to avoid the loss of water as they are exposed under high temperature.