They do the same thing that all living and breathing things do! They breathe! When they breathe they are doing the same thing you are doing all day everyday. Inhaling oxygen and exhaling carbon dioxide.
Catalase.is an enzyme in the liver that breaks down harmful hydrogen peroxide into oxygen and water.
Answer: Hairlessness and Glands
explanation:Another notable similarity between the two groups is minimal hair. Both hippos and whales possess barely any hair on their bodies. They do not have sweat glands, either. These are both characteristics that can assist them in their aquatic lifestyles.