Question

What is the layer of the earth where mantle convection occurs and on which the earth's crust rests?

Answer 1

In the passage this question was provided for, you should have been able to locate the fallowing text: "the outer layer of the mantle; made up of plastic or semi-molten rock" and many others to imply this answer.

Answer: Asthenosphere

Answer 2

the asthenosphere. It is a partial molten region of the upper mantle. The convection with it, helps move the earths crust that lies on it, which is how tectonic plate movements happen.