Which two gases dominate Earth's surface atmosphere?
Show answer & explanation
Correct answer: C
Explanation
The two most abundant gases in Earth's terrestrial atmosphere are nitrogen (N₂) and oxygen (O₂). Nitrogen makes up about 78% of the atmosphere, while oxygen is the second most abundant gas, accounting for about 21%. Together, they make up about 99% of the atmosphere's total volume.
Other options:
O₂ & Ar (argon is only 0.93%)
N₂ & Ne (neon is in very small amounts)
O₂ & Ne (neon is in very small amounts)