GEOLOGY

Detailed explanation-1: -Gases. The most abundant naturally occurring gas is nitrogen (N2), which makes up about 78% of air. Oxygen (O2) is the second most abundant gas at about 21%. The inert gas argon (Ar) is the third most abundant gas at 0.93%.

Detailed explanation-2: -Nitrogen and oxygen account for 99 percent of the gases in dry air, with argon, carbon dioxide, helium, neon, and other gases making up minute portions.

Detailed explanation-3: -The other primary reason is that, unlike oxygen, nitrogen is very stable in the atmosphere and is not involved to a great extent in chemical reactions that occur there. Thus, over geological time, it has built up in the atmosphere to a much greater extent than oxygen.

Detailed explanation-4: -Nitrogen is the most abundant gas present in the atmosphere constituting 78% of air. Oxygen makes up about 21% of air by volume and is the second most abundant gas present in the atmosphere.

Detailed explanation-5: -there would be more acidic oxides and more erosion on land. more ozone in the atmosphere. If the atmosphere composition is 21% oxygen and 78% nitrogen, why did we evolve to “breathe” oxygen instead of nitrogen? Because nitrogen is completely useless for the task.