How are mid-ocean ridges and deep-ocean trenches related to plate tectonics?

The movement of Oceanic and Continental plates, which cover the earth, is caused by convection currents. Convection currents are created by rising and falling heat in the earth's mantle. The plates are pushed together and apart, creating ridges or trenches. For example, when two oceanic plates are pushed apart from each other, the magma rises to the surface between the plates and creates a ridge. Mid-ocean ridges are created by the pulling apart of plates, while deep-ocean trenches are created by the collision of plates. A mid-ocean ridge is an under-water mountain range formed by divergent plate boundaries where two oceanic plates are moving away from each other. Deep-ocean trenches, on the other hand, are formed by the collision of the plates. When one plate is pushed beneath the other, it creates an under-water trench. It is this plate movement that is responsible for the formation of mid-ocean ridges and deep-ocean trenches.