Final answer:
Narrow leaves help plants in the dune by reducing water loss through transpiration. They have a smaller surface area and sunken stomata, which minimize evaporation.
Step-by-step explanation:
Narrow leaves help plants in the dune by reducing water loss through transpiration. This is achieved by two attributes of the leaves: having a smaller surface area and sunken stomata. The reduced surface area decreases the exposure to air and sunlight, minimizing evaporation. Sunken stomata, which are small openings on the leaf surface, also help to decrease water loss.