Answer:
Mid-ocean ridges are the mountain ranges within the ocean environment. They are formed when oceanic plates collide during plate techtonics and magma rises above the oceanic lithosphere. Typically, it results into uplifting of the thin oceanic crust and making mountains. The magma solidify after interaction with the water and results into formation of new lithosphere.
Accretion is the phenomenon during which new material is added and landmass (lithosophere) is created during plate tectonics. Therefore, accretion takes place during formation of mid-oceanic ridges. Principally, when a plate subducts below the other plate, some material scrap off from the subducting plate and then deposit above the plate hence making accretionary wedge.