AP BIOLOGY

Detailed explanation-1: -This kind stem is known as succulent. The stems are generally green in colour and are capable of performing photosynthesis. There is a waxy coating on the stem that prevents loss of water. The leaves of the cactus plants are modified into spines.

Detailed explanation-2: -Cactus survive in deserts due to following adaptations: It has a flat green stem to store water and prepare food by photosynthesis. The stem is also covered with a thick waxy layer, which helps to retain water.

Detailed explanation-3: -Cacti are plants that have succulent stems, pads or branches with scales and spines instead of leaves. Cactus pads are actually modified stems with a waxy coating.

Detailed explanation-4: -Phylloclades. The cactus stems are modified into phylloclades. A phylloclade is a flattened stem of several internodes functioning as a leaf in some xerophytic plants. They contain chlorophyll and carry out photosynthesis. On the surface of the phylloclade, clusters of spines are formed.

Detailed explanation-5: -A thick, waxy coating keeps the water inside the cactus from evaporating. Many cacti have very long, fibrous roots, which absorb moisture from the soil.