Question

why is the epidermis present as a thick waxy coating of cutin in desert plants

Answer 1

To prevent the loss of water and protection from predators.

Answer 2

Hi friend,

In desert plants epidermis is present as a thick waxy coating of cuticle this is because the rate of evaporation {transpiration}is high there...
the thick layer prevents6 the water from evaporating from the plant..thus, desert plants
are able to survive high temperatures.

hope it helps..☺️