Answer:
Nitrogen
Explanation:
Composition of the Atmosphere
The atmosphere contains several gases, most of them in small amounts, which may include some pollutants and greenhouse gases.
The most abundant gas in the atmosphere is nitrogen (78%), followed by oxygen (21%) as the second. The inert gas called Argon is the third most abundant gas in the atmosphere (less than 1%).
Finally, the fourth most abundant gas in Earth's atmosphere is Carbon dioxide
