The cuticle prevents water loss in leaves

Steps:

• Recall that the leaf cuticle is a waxy outer layer on the epidermis.
• Identify its primary function: to act as a barrier against evaporation.
• Evaluate each option against this function and leaf anatomy.
• Select the option matching the non-cellular, impermeable nature of the cuticle.

Why D is correct:

• The cuticle is a thin, waxy, non-cellular layer that covers the epidermis, reducing transpiration by preventing water vapor escape, as defined in plant physiology.

Why the others are wrong:

• A: The cuticle is impermeable to water, not allowing entry; it blocks loss.
• B: This describes the palisade mesophyll, not the cuticle, which lacks cells and chloroplasts.
• C: The upper epidermis cells are transparent for light, but the cuticle is non-cellular and waxy, not a layer of cells.

Final answer: D