hydrogen, helium, and water vapor hydrogen, methane, and ozone carbon dioxide, water vapor, and nitrogen carbon dioxide, methane, and helium
I gave my students this multiple choice question: In addition to oxygen, which gases make up the largest percentage of Earth's atmosphere?

Only one answer is correct among these 4 choices:
- hydrogen, helium, and water vapor
- hydrogen, methane, and ozone
- carbon dioxide, water vapor, and nitrogen
- carbon dioxide, methane, and helium

Could you tell me which one is correct?

carbon dioxide, water vapor, and nitrogen