AP BIOLOGY

Detailed explanation-1: -The deserts are regions with hot and dry climates all the year round. Lack of rainfall or very little rainfall makes the climate extremely dry for the survival of plants. Hence the plants adapt to this by storing water in stems, roots, or fleshy leaves and by employing CAM process.

Detailed explanation-2: -CAM plants naturally grow in climates that are usually hot and dry. To avoid drying out, they only open their stomata at night to allow CO2 inside for the assimilation. They bind the CO2 and store it as malate.

Detailed explanation-3: -All plants use C3 photosynthesis, which has been supplemented in some species with Crassulacean acid metabolism (CAM) and C4 photosynthesis. These two pathways are adaptations to dry environments.

Detailed explanation-4: -CAM plants have evolved a specialized type of photosynthetic adaptation that allows them to live under conditions of severe water deficit and in semi-arid and arid regions of the world including deserts.

Detailed explanation-5: -Complete answer: Option A: I only-CAM plants grow in hot and dry climates due to lack of sufficient water. Crassulacean acid metabolism is a carbon-mediated pathway. Plants which survive in dry conditions are desert plants only.