Question

How do whales differ from fish

Answer 1

They are a mammal. Meaning, they need oxygen, they give birth and produce milk.

Answer 2

Fish have gills which extract oxygen from the water and thus allow it to live underwater its entire life. Whales on the other hand do not have gills but instead have one or two blowholes that connect to its lungs which allow the whale to breathe in air.

Hope this helps.