They both have rocky surfaces. They both have active volcanoes. They both have similar atmospheres. They both have the same gravitational pull.
I gave my students this multiple choice question: Which characteristic do both the Moon and Earth share?

Only one answer is correct among these 4 choices:
- They both have rocky surfaces.
- They both have active volcanoes.
- They both have similar atmospheres.
- They both have the same gravitational pull.

Could you tell me which one is correct?

They both have rocky surfaces.