Question

In some plants like desert plants, epidermis has a thick waxy coating of cutin on it's outer surface. What's the reason

Answer 1

in desert area, the rate of evaporation is greater as compared to other places since it has a dry climate. so in order to prevent loss of water (transpiration), the desert plants have a thick waxy coating in their epidermis.

Answer 2

cuz there is more evaporation in desert... and i.e they'll lose more water. that's why they've thick waxy coating to prevent transpiration.