One adaptation that is unique to marine mammals is they

can slow their heart beat down.

are warm-blooded.

breathe air through their lungs.

nurse their young.

answer; /// i believe the name your looking for is called (plaque)or check good luck

sorry to break it to ya but no one can answer your question it's just

jk but i am serious about the part that most people cant answer it beacuse you did not mention the section you are talking about. but it would if you added some detail and were a bit more specific.