Texes Social Studies Content Practice Exam

Which layer of the Earth is primarily liquid?

1. A) Crust

2. B) Mantle

3. C) Outer core

4. D) Inner core

The correct answer is: C) Outer core

The outer core is primarily liquid due to the high temperatures and pressures found at that depth within the Earth. Made up mainly of molten iron and nickel, the outer core lies beneath the mantle and surrounds the solid inner core. The movement of the liquid in the outer core is also responsible for generating Earth's magnetic field through the dynamo effect. In contrast, the crust is the Earth's outermost layer, which is solid and consists of rock and soil. The mantle, located below the crust, is mostly solid but behaves like a viscous fluid over long periods, allowing for slow convection currents. The inner core, while extremely hot and solid due to immense pressure, is primarily composed of iron and nickel. Thus, the outer core is unique among these layers for its liquid state.