What is the role of the mid-ocean ridge in the movement of lithosperic plates?

The mid-ocean ridge is formed by plate tectonics and consists of mountains forming an underwater mountain system. Every ocean contains parts of the mid-ocean ridge system. Lithosphere is the colder, denser part of the mantle that, together with the crust, comprises the oceanic plates. The role of the mid-ocean ridge in the movement of lithosphere plates is to fill the gap of separating plates.