What is the state of matter of the rock within the stiffer mantle?

Question

I think I have the answer but I'm not sure and I don't want to risk it. All help is appreciated. :)

Answer 1

The stiffer mantle is actually still a solid. Although the rock is solid, it can exhibit properties of plasticity under the intense conditions present. This plastic behavior allows the rock to slowly flow over long periods of time, a process known as mantle convection. This flow of solid rock is a significant driver of tectonic plate movements and the associated geological activities on Earth's surface.