Question

what is an example of a physiological adaptation in emperor penguins?
huddling together in the winter and rotating to keep warm
controlling their heart rates to slow down to use less oxygen and go longer without food
the coloring of their bodies to camouflage in the water

Explanation:

Physiological adaptations involve internal body processes. Controlling heart - rate (a body process) to use less oxygen and survive longer without food is a physiological adaptation. Huddling is a behavioral adaptation (a group action), and body coloring is a structural (physical trait) adaptation.

Answer:

controlling their heart rates to slow down to use less oxygen and go longer without food