Animals that live in the desert a. hibernate in the winter b. include camels, moose, and various reptiles c. usually have thin skin to absorb water d. are usually nocturnal

The answer is D.  Most desert animals are nocturnal.  The exception here in the desert where I live is lizards and birds.  They're all over the place during the day.  But if you go out into the desert at night you can find rattlesnakes, rabbits, foxes, scorpions, kangaroo rats, and all sorts of critters.

the answer would be..

b. sucking