Sea animals like dolphins and whales do not have gills. They breathe in air through blowholes that are located on the upper part of their head. (1 Mark)
This allows them to breathe in air when they swim near the surface of the water. Lungs then help in absorbing the oxygen from it. (1 Mark)
They can stay inside water for a long time without breathing. They come out to the surface of the water, when they need to breathe in air from the atmosphere. (1 Mark)