A whale is different from a fish in many ways. One thing that makes a whale different is that it is a mammal. This means that it is similar to humans in that it needs air to breathe. Fish do not use air. They use their gills to breathe. This means that a whale has to come up for fresh air every few minutes. It holds its breath and can hold its breath for many minutes because of its large lungs. Which sentence would best support the main idea?
A.
Being a mammal also means that whales are warm-blooded, and they have at least a few hairs on their bodies.
B.
A flipper or fluke slapping is when a whale slaps the water with its flipper or fluke.
C.
Over 70 species of whales, dolphins, and porpoises live in the world's oceans.
D.
Sounding is the term used for whale diving.

i think its a but i wanna get it right