The outer core of Earth is molten, but the inner core is solid. The reason is that the
A) inner core has a different composition than the outer core, with a higher melting point.
B) lower pressure in the inner core allows the material to freeze out of the molten rock.
C) melting point of the iron-nickel mixture is raised above the actual temperature by the extremely high pressure.
D) temperature is lower in the inner core than in the surrounding region.

Question

Quizplus · Accepted Answer

The inner core is solid despite being hotter than the outer core because the extremely high pressure increases the melting point of the iron-nickel mixture, keeping it in a solid state.

The Outer Core of Earth Is Molten, but the Inner