One advantage to being an endotherm (instead of an ectotherm) is that an endotherm
a. can generate its own body heat.
b. needs less energy to maintain homeostasis.
c. needs more energy to maintain homeostasis.
d. can increase its body heat by sweating.

An endotherm, also called as a warm-blooded organism, has the ability to generate heat internally. One advantage to being an endotherm, instead of an ectotherm, is that an endotherm can generate its own body heat. This kind of organism can create a favorable level of body heat that is independent of its environment. Endotherms include mammals and birds. 

The direction a chemical reaction occurs is represented by an arrow