Question

Which of the following statements accurately explains how Earth's atmosphere supports life?

A. Earth's atmosphere contains 78 percent oxygen, which is essential for life.
B. Earth's atmosphere contains 21 percent oxygen, which many life forms need to survive.
C. Earth's atmosphere contains more oxygen then carbon dioxide.
D. Earth's atmosphere contains carbon dioxide, which all life forms breathe in.

Answer 1

we know its not D because humans dont breathe in carbon dioxide we just breath it out

Answer 2

i think its a

Answer 3

Well, I think it would prolly be A, since it does contain 78% oxygen, and it's what humans breathe in, and, in turn, we breathe out carbon dioxide. It's definitely not B either, but let me check C.

Answer 4

Apparently, the amount of CO2 in the air keeps rising, so we don't know if C is right or not in most cases, so I'd just say A.

Answer 5

I know I answered this before. I swear this is a test or something.

Answer 6

Probably :<