Question

why do desert plants have scale or spine like leaves

Answer 1

The leaves of cactus are modified leaves. They are green in colour and has thrones which are actually the leaves. These thrones prevent the loss of water from the plant.

Answer 2

1) Needle shape helps the leaves to retain moisture, preventing water loss as the stomatas are sunken and tightly packed in needle like leaves. 2)Needle shape gives them ability to shed snow as pine trees are found in cold regions.