Which two gases make up a combined total of 99% of clean, dry air in the homosphere?
A) carbon dioxide and water vapor
B) nitrogen and oxygen
C) nitrogen and argon
D) oxygen and carbon dioxide

Question

Quizplus · Accepted Answer

The two gases that make up a combined total of 99% of clean, dry air in the homosphere are nitrogen (78%) and oxygen (21%). Carbon dioxide, water vapor, and argon make up less than 1% of the atmosphere.

Which Two Gases Make Up a Combined Total of 99