What is the cuticle on a leaf surface?

• A. It is the outermost part of the leaf with stomata.
• B. It is a waxy layer that retards movement of water and gases.
• C. It is where photosynthesis primarily occurs.
• D. It is the site where nutrients are stored.

Answer: (B)

The cuticle is a waxy, protective layer on the leaf surface that slows the movement of water and gases. It coats the epidermis and is mainly made of cutin and waxes, forming a hydrophobic barrier that helps prevent water loss and restricts gas diffusion. Stomata are openings that allow gas exchange and are bordered by guard cells; they sit in the epidermis, but the cuticle itself is the outer coating over those cells. Photosynthesis happens mainly in internal leaf tissues like the mesophyll, where chloroplasts are located, not in the cuticle. Nutrients aren’t stored in the cuticle either. So the best description is a waxy layer that retards movement of water and gases.