Question

if you are a desert plant, the best time to get co2 is ______ . day night

Explanation:

Desert plants (like succulents with crassulacean acid metabolism, CAM) open stomata at night to take in CO₂ (to minimize water loss during hot, dry days). During the day, stomata close, and they use stored CO₂ for photosynthesis. So the best time for a desert plant to get CO₂ is night.

Answer:

night (the option: night)