Question

Why are the leaves in a cactus plant modified to form spines? How, then, does the plant make food?

Answer 1

Cactus grows in desert environment, where there is scarcity of water. The leaves of cactus are modified into spines, to prevent water loss from the surface of leaves. The green stem of the cactus plant contains chlorophyll. Thus, the stem is the centre of photosynthesis in the cactus plants instead of the leaves.