PLEASE HELP ME ! When did whale ancestors begin living full time in the water?

A) before they nursed under water

B) after they began eating a carnivorous diet

C) before they evolved gills

D) after they lost their hind legs

40 million years ago

The earliest whales that we think were fully aquatic, that is, they never left the water, are found around 40 million years ago, during the middle Eocene. That means that the transition from terrestrial animals to fully aquatic animals took about 12 million years.

Explanation:

"d.) carbon dioxide and hydrogen sulfide"

frogs. the lower the ph the higher the acid content. frogs have the highest tolerance in this scenario.