Question

How much of Earth's atmosphere is made up of nitrogen and oxygen?

A. Between 25 and 75 percent
B. Close to 99 percent
C. Less than 1 percent
D. 100 percent

Answer 1

B. CLOSE TO 99% WOULD BE THE CORRECT ANSWER

Answer 2

The right answer is the option B. Close to 99 percent. The atmosphere is a mixture of gases: nitrogen, oxygen, CO2, H2O, argon, among others. Nitrogen is about 78% and oxygen is about 21%, so they two together constitute about 99 percent of the Earth's atmosphere.