Respuesta :
Answer:
A. Mantle convection
Explanation:
Ridges are formed over the divergent plate boundaries, it can be pushed by the mantle plume volcanism originated by the core mantle boundary at the Asthenosphere region over the divergent plate boundary. Seafloor spreading is the one of the evidences of plate tectonics theory. Subduction of the plate is the result of ridge push and slab pull, oceanic plate is less dense so its under beneath the high denser continental plate.