Which of the following plant structures lacks a waterproof cuticle?

Step 1: Analyze the question We need to find the plant part that does not have a waterproof cuticle. The cuticle is a waxy, water-resistant layer covering the epidermis.

Step 2: Explain the concept The cuticle is made of cutin (a waxy substance). Its main job is to reduce water loss by evaporation. Parts of the plant that are exposed to air, such as leaves and green stems, need this protection to avoid drying out.

Roots are different. Their main job is to absorb water and mineral salts from the soil. A waterproof layer would block this absorption. Root hairs, which are tiny extensions of the root epidermal cells, have very thin walls and no cuticle, so water can pass in easily by osmosis.

Step 3: Go through the options

• A. Leaf: has a cuticle, especially on the upper surface, to reduce water loss. ✗
• B. Stem: young green stems have a cuticle on the epidermis. ✗
• C. Root: absorbs water, so it lacks a waterproof cuticle. ✓
• D. Shoot: the shoot system includes the stem and leaves, which are cuticle-covered. ✗

Step 4: Answer The correct answer is C. Root.

Tip: Link function to structure. Parts that absorb water (roots) have no waterproof layer. Parts that must save water (leaves, stems, shoots) have a cuticle. If you remember "roots absorb, so no wax," you can answer this kind of question quickly.