Final answer:
Seafloor spreading is driven by convection currents in the mantle and involves the formation of new crust at mid-ocean ridges. The two primary driving forces of plate motion are ridge push and slab pull.
Step-by-step explanation:
Seafloor spreading is a geologic process where new oceanic crust is formed through volcanic activity at mid-ocean ridges and then spreads away from the ridge. As molten rock rises to the surface at the ridge, it cools and solidifies, forming new crust. This process is driven by convection currents in the mantle, which cause the plates to move.
There are two primary driving forces of plate motion: 1) Ridge push, which occurs at mid-ocean ridges where the lithosphere is elevated due to the formation of new crust. As the lithosphere is pushed up, it creates a slope that drives the plates away from the ridge. 2) Slab pull, which occurs at subduction zones where one plate is forced beneath another. The sinking plate pulls the rest of the plate along with it, causing plate motion.