•how does convection drive plate movement?

Convection drives plate movement because of high convection current on the Earth’s core.  It makes molten rocks to move in molten layer.

Explanation:

In the aesthenosphere, high convection currents pass heat on the surface, where less dense magma leaves break down plates in distribution centres and create different plate boundaries.

When the plate moves away from the propagation centres, they also cool down to higher-density rocks, which are part of the oceanic crust consumed in ocean subduction areas. Then, the crust returns to aesthenosphere.

Generally, the heat generated by the radioactive decomposition of elements deeper in the Earth produces magma (molten rock) in aesthenosphere. It (70 to 250 km) is a part of mantle, the central globe, extending over 2,900 km.