Question

explain how convection currents cause the crust of the earth to move?

Answer 1

At the top of the mantle, the rock encounters the thin crust, and, as it pushes it aside, lava flows out from the mantle to form new oceanic crust. As this happens, the plates smash into each other, slide past each other or are pushed under another plate. This movement of the plate along with the upwelling of the mantle by the convection currents may also cause secondary actions that assist in plate movement.

Answer 2

thanks @Simon_Said_So