Question

mid-term exam
which layer of the earth allows plates to slide around on its semi - plastic surface?
lower mantle
asthenosphere
troposphere

Explanation:

The asthenosphere is a semi - plastic layer in the upper mantle. It is less rigid than the lithosphere above it. Plate tectonics theory states that the lithospheric plates (which include the crust and the rigid part of the upper mantle) "float" and move on the more ductile asthenosphere. The lower mantle is more rigid and less involved in the direct movement of plates. The troposphere is part of the Earth's atmosphere, not a layer of the Earth's interior related to plate movement.

Answer:

B. asthenosphere