The Earth is composed of multiple layers, which can be defined either by composition or by mechanical properties. This layer is key to plate movement. It is a solid but flows like a very viscous fluid. It is the A. mesosphere B. lower mantle C. lithosphere D. asthenosphere.

The correct answer is - asthenosphere.

Explanation:

The asthenosphere is the upper layer of the Earth's mantle present below the lithosphere. It is a solid layer but viscous or flow-like liquid that allows continental drift development.

The asthenosphere is played a critical role in the movement of plates as it has plates that move across the face of Earth's surface. This layer is found from 100 to 700 km below the surface of the Earth.

b

explanation:

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