Almost 99% of Earth's atmosphere is made up of two gases. What are the two gases and the percents of each?

Question

Responses

A 21% oxygen and 78% nitrogen21% oxygen and 78% nitrogen

B 21% water vapor and 78% oxygen21% water vapor and 78% oxygen

C 21% nitrogen and 78% oxygen21% nitrogen and 78% oxygen

D 21% carbon dioxide and 78% oxygen21% carbon dioxide and 78% oxygen

Answer 1

The correct response is:

A 21% oxygen and 78% nitrogen.

These two gases, oxygen and nitrogen, make up the majority of Earth's atmosphere.