The earth's atmosphere, which we refer to as air, is a mixture of approximately
A)$ 78 \% $ oxygen, $ 21 \% $ nitrogen, and less than $ 1 \% $ carbon dioxide.
B) $ 78 \% $ nitrogen, $ 21 \% $ oxygen, and less than $ 1 \% $ argon.
C)$ 78 \% $ oxygen, $ 21 \% $ carbon dioxide, and less than $ 1 \% $ helium.
D) $ 78 \% $ oxygen, $ 21 \% $ water vapor, and less than $ 1 \% $ ozone.

Question

The earth's atmosphere, which we refer to as air, is a mixture of approximately 
A)$ 78 \% $ oxygen, $ 21 \% $ nitrogen, and less than $ 1 \% $ carbon dioxide.
B) $ 78 \% $ nitrogen, $ 21 \% $ oxygen, and less than $ 1 \% $ argon.
C)$ 78 \% $ oxygen, $ 21 \% $ carbon dioxide, and less than $ 1 \% $ helium.
D) $ 78 \% $ oxygen, $ 21 \% $ water vapor, and less than $ 1 \% $ ozone.

Quizplus · Accepted Answer

The correct composition of the Earth's atmosphere is approximately 78% nitrogen, 21% oxygen, and less than 1% argon, along with traces of other gases.

The Earth's Atmosphere, Which We Refer to as Air, Is 78% 78 \% 78%

The Earth's Atmosphere, Which We Refer to as Air, Is $78 \%$