lithosphere and mesosphere inner core and outer core outer core and mantle mantle and crust
I gave my students this multiple choice question: Some of the thermal structure of Earth is the result of a combination of chemical composition, temperature, and pressure. Which is a boundary that best demonstrates a contact point between layers having relatively the same temperature and chemical composition?

Only one answer is correct among these 4 choices:
- lithosphere and mesosphere
- inner core and outer core
- outer core and mantle
- mantle and crust

Could you tell me which one is correct?

inner core and outer core