GENERAL KNOWLEDGE

Detailed explanation-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.

Detailed explanation-2: -Leaves are modified into spines to prevent loss of water.

Detailed explanation-3: -In case of cactus plants the leaves are modified into spines.

Detailed explanation-4: -To prevent water loss, cacti are covered with a waxy substance called a cuticle. Another way they conserve water is by opening structures called stomata at night, rather than during the day like most plants. Stomata are microscopic pores on the plant through which carbon dioxide enters for photosynthesis.