C because the heart pumps normally with a constant pressure but when it is lower it needs to push harder to get the blood to where it needs to go causing it to malfunction
I think it would be to exchange gases. When you think about it, plants in the past were always underwater. They didn't have any air. Now, they are on land and need to be able to exchange gases from the leaves to the roots.
Answer: im not sure if im correct but i think it is c d e
Explanation:
Nearly 78 percentage of the air
