made of hydrogen and helium. older than other objects in the solar system. the source of most heat and light energy. the strongest source of gravity in the solar system.
I gave my students this multiple choice question: The planets in the solar system revolve around the Sun because the Sun is

Only one answer is correct among these 4 choices:
- made of hydrogen and helium.
- older than other objects in the solar system.
- the source of most heat and light energy.
- the strongest source of gravity in the solar system.

Could you tell me which one is correct?

the strongest source of gravity in the solar system.