Answer:
new volcanoes
Step-by-step explanation:
The mid-ocean ridges occur at places where there is a divergent plate boundary between two plates, and the boundary is located on the ocean floor. At this type of boundaries, the tectonic plates are moving away from each other, and there is constant volcanic activity between them.
The volcanic activity produces lot of magma, which quickly cools off in the water and piles up, creating underwater mountain ranges known as mid-ocean ridges. This constant piling of igneous rocks from the rising magma, produces new crust, or rather creates new ocean floor.
The old ocean floor is pushed aside, and there is a general principle that the crust at the mid-ocean ridge is the youngest, and the further away a place it is from it, the older the crust is.
Along all of the mid-ocean ridge there is constant volcanic activity, and that volcanic activity creates lot of new volcanoes on the ocean floor.