What is the composition of clean, dry air?

Clean, dry air is primarily composed of nitrogen and oxygen, with nitrogen being the dominant component. The correct composition, approximately 78% nitrogen and 21% oxygen, reflects the typical atmospheric conditions found at sea level.

Nitrogen is an inert gas that plays a crucial role in the atmosphere, serving to dilute oxygen and reduce the risk of combustion. Oxygen is vital for life, as it is essential for respiration in humans and many other organisms.

A mixture with 50% nitrogen and 50% oxygen would be unusual and not representative of the Earth's atmosphere. Additionally, the option stating 100% argon would imply an inert atmosphere with no oxygen or nitrogen present, which would not support life as we know it.

Understanding the correct proportions of gases in the atmosphere is essential for various scientific fields, including environmental science and meteorology, as it influences air quality, climate, and various biological processes.