...some desert animals
a) Arthropods have waxy cuticles, land snails have shells, and vertebrates are covered by a multi-layer skin comprised of dead, keratinized cells.
b) Some desert animals are nocturnal. Being active at night reduces dehydration and some (e.g., kangaroo rat) produce large amounts of metabolic water.
c) Excretory organs of terrestrial animals are adapted to conserve water while eliminating wastes.