Explain the mantle convection cell model and what it describes

Answer 1

A convection cell is a heat system formed primarily from decay of radioactive elements in Earth's core and lower mantle. In the mantle convection cell model heat from the core, supplemented by heat generated from radioactive decay, drives large mantle convection cells. In this manner, hot rock from the interior rises toward the surface, loses heat to the overlying lithosphere, becomes denser as it cools, and then sinks back into the interior where it is heated, and the process repeats itself. The convection cells therefore determine the location of spreading ridges and trenches, with the lithosphere lying above the convection cells. Spreading ridges mark the ascending limbs of adjacent convection cells and trenches are present where convection cells descend back into Earth's interior. Thus, each plate corresponds to a single convection cell that moves as a result of the convective movement of the cell itself. This model describes one mechanism for continental drift theory.