Question

The inner and outer core of the earth (C), beneath the mantle (B), are the deepest and hottest layers. The inner core is made of iron and nickel and lies at the very center of the Earth. It has a temperature of about 5,500 °C, is about 1,220 km in diameter, and is surrounded by the liquid outer core. What is another characteristic of the inner core?
A It is a molten mass of magma, much like the mantle.
B It fluctuates between solid and liquid, depending on the temperature.
C The pressure there is so great that it cannot melt and it is solid.
D It rises up through the other layers of Earth to become the magma of volcanoes.

Answer 1

C — The pressure at Earth's center is so great that, despite the high temperature, the iron–nickel is kept solid. The outer core above it is the liquid layer.