The hottest layers are closest to the core. The more liquid layers are closest to the crust. The lightest layers are closest to the core. The more metallic layers are closest to the crust.
I gave my students this multiple choice question: Which of these best describes the relationship between Earth's layers?

Only one answer is correct among these 4 choices:
- The hottest layers are closest to the core.
- The more liquid layers are closest to the crust.
- The lightest layers are closest to the core.
- The more metallic layers are closest to the crust.

Could you tell me which one is correct?

The hottest layers are closest to the core.