What is the cause of the plate tectonic activity?

Plate tectonics is primarily caused by Earth's cooling mechanism, which generates convection currents in the planet's mantle that trigger slow but constant tectonic plate movement

Plate tectonic activity is caused by thermal convection, where heat from the Earth's interior causes currents of hot rising magma and cooler sinking magma to flow, moving the plates of the crust along with them.