Which compositional layer is a hot, convecting layer of rock?

Like road tar softened by the heat of the sun, this part of the mantle is somewhat soft—it can bend like plastic. This soft layer is called the asthenosphere (as then uh sfeer). In Greek, asthenes means “weak.” Although the asthenosphere is softer than the rest of the mantle, it's still solid.

Explanation:

hope this helps :D