Question: What are the 3 most common gasses in earth's atmosphere?
Disambiguated questions and answers: question: What is the most common gas in earth's atmosphere by volume?
What is the second most common gas in earth's atmosphere by volume?
What is the third most common gas in earth's atmosphere by volume?
answer: N
N2
dinitrogen
nitrogen
nitrogen gas
Diatomic oxygen gas
O2
oxygen gas
Oxygen
Argon
argon gas
Natural Questions answer: argon
oxygen
nitrogen (from the Wikipedia article "Atmosphere of Earth")