heat being added to oxygen helium mixing with oxygen heat combining with oxygen hydrogen and oxygen combining
I gave my students this multiple choice question: Look at the equation. 2H_{2} + O_{2} -> 2H_{2}O What does the equation show?

Only one answer is correct among these 4 choices:
- heat being added to oxygen
- helium mixing with oxygen
- heat combining with oxygen
- hydrogen and oxygen combining

Could you tell me which one is correct?

hydrogen and oxygen combining