Question

What is the force responsible for seafloor spreading and the formation of new ocean floor at mid-ocean ridges?

a. the destruction of ocean crust in trenches
b magma from the mantle is forced up toward the ocean ridge
c. ocean crust sitting on the asthenosphere d. the differences in mass of the ocean and continental plates​

Answer 1

B. Magma from the mantle is forced up toward the ocean ridge.

Seafloor spreading is a process by which new oceanic crust is created at mid-ocean ridges and the older crust is destroyed at oceanic trenches. The process is driven by the movement of the Earth's tectonic plates. At the mid-ocean ridges, the plates are moving apart, creating a space between them that is filled by magma from the mantle. The magma rises to the surface and cools, forming new oceanic crust.