Find out the reason behind the following statements:
$(a)$ Epidermis is thicker in desert plants,though it is usually single-layered.
$(b)$ Presence of a waxy layer (secreted by the epidermis) on the outer surface of plants.
$(c)$ Meristematic cells have a prominent nucleus and dense cytoplasm but lack a vacuole.

(N/A) In desert plants,the epidermis is thicker due to the presence of a thick waxy coating of cutin to prevent water loss.
$(b)$ The waxy layer of cutin present on the outer surface of plants is water-resistant and protects the plant against excessive loss of water through transpiration.
$(c)$ Vacuoles provide turgidity and rigidity to mature plant cells. Since the primary role of meristematic tissue cells is to divide continuously to facilitate growth,they do not require large vacuoles,which would otherwise hinder the rapid process of cell division.