GEOLOGY

Detailed explanation-1: -It is mostly solid rock, but less viscous at tectonic plate boundaries and mantle plumes. Mantle rocks there are soft and able to move plastically (over the course of millions of years) at great depth and pressure. The transfer of heat and material in the mantle helps determine the landscape of Earth.

Detailed explanation-2: -The pressure in the mantle increases from a few hundred megapascals at the Moho to 139 gigapascals (20, 200, 000 psi) at the core-mantle boundary.

Detailed explanation-3: -Pressures in the lower mantle start at 237, 000 times atmospheric pressure (24 gigapascals) and reach 1.3 million times atmospheric pressure (136 gigapascals) at the core-mantle boundary.

Detailed explanation-4: -The inner core experiences the highest pressure.