Eli5: How was the first ancient animal to ever step (foot?) out of the water, able to survive breathing air instead of water?

Question

Eli5: How was the first ancient animal to ever step (foot?) out of the water, able to survive breathing air instead of water?

In: Biology

Answer 1

> How was the first ancient animal to ever step (foot?) out of the water, able to survive breathing air instead of water?

The first animal to do that was a single celled creature, and used osmosis to pull oxygen out of the air or the water.