Which layer allows plates to move because it is partially molten?

Which layer allows plates to move because it is partially molten?

• A. Lithosphere
• B. Asthenosphere
• C. Mesosphere
• D. Core

Answer: (B)

The main idea is that the layer beneath the rigid tectonic plates is weak and can flow. This layer, called the asthenosphere, is partially molten, so rocks there behave plastically and deform slowly rather than breaking. That ductile behavior lets the overlying lithosphere ride and slide on top of it, enabling continents and oceanic plates to move. The lithosphere above is rigid and forms the plates themselves, while the mesosphere is deeper in the mantle and more rigid, and the core sits far below as the Earth's center. So the asthenosphere is the layer that allows plate motion because of its partially molten, flowing nature.

The main idea is that the layer beneath the rigid tectonic plates is weak and can flow. This layer, called the asthenosphere, is partially molten, so rocks there behave plastically and deform slowly rather than breaking. That ductile behavior lets the overlying lithosphere ride and slide on top of it, enabling continents and oceanic plates to move. The lithosphere above is rigid and forms the plates themselves, while the mesosphere is deeper in the mantle and more rigid, and the core sits far below as the Earth's center. So the asthenosphere is the layer that allows plate motion because of its partially molten, flowing nature.