What part of the leaf primarily protects it from air drying?

The cuticle is a waxy layer that covers the surface of the leaves and stems of plants. Its primary function is to serve as a protective barrier against water loss. By being hydrophobic, the cuticle minimizes evaporation of water from the leaf surface, which is essential for maintaining hydration and overall plant health. This adaptation is particularly important in environments where water conservation is critical. The thickness and composition of the cuticle can vary depending on the plant species and its environment, further enhancing its protective function against desiccation.