All planets can support life; moons cannot. All planets have atmospheres; moons do not. All planets orbit the Sun; all moons orbit planets. All planets are larger than all moons.
I gave my students this multiple choice question: What is the main difference between planets and moons in our solar system?

Only one answer is correct among these 4 choices:
- All planets can support life; moons cannot.
- All planets have atmospheres; moons do not.
- All planets orbit the Sun; all moons orbit planets.
- All planets are larger than all moons.

Could you tell me which one is correct?

All planets orbit the Sun; all moons orbit planets.