Answer:

Dolphins have a layer of blubber or fat under the surface of their skin. This blubber aids in streamlining the dolphin's body, insulating in cool water and keeping the dolphin's body buoyant in the water.

Answer:

Blubber

This blubber helps to streamline the body of the dolphin, insulate it in cold water, and keep the body of the dolphin buoyant in the water.