hydrogen, oxygen 2 hydrogen, 1 oxygen 2 hydrogen, 2 oxygen
I gave my students this multiple choice question: What atoms combine to make up a molecule of water? 1. 1 hydrogen, 1 oxygen 2.

Only one answer is correct among these 4 choices:
- hydrogen,
- oxygen
- 2 hydrogen, 1 oxygen
- 2 hydrogen, 2 oxygen

Could you tell me which one is correct?

2 hydrogen, 1 oxygen