Why does molten rock from the mantle come to the surface at the ridges?

Please answer this question along with another question.My other question is: Why is rock formed at the ridges called new rock?I would appreciate it if you would answer if you know it.Why does molten rock from the mantle come to the surface at the ridges?
Magma rises to the surface at the ridges because the ridges are literally where the plate are pulling away from each other. As they pull away, they create an area where there is no crust, so the magma rises and becomes rock in order to ';plug the hole.';





Since the rock just came up and cooled, it's ';new oceanic rock.'; Because... it's new rock. It's the youngest rock. It just came out of the ground and cooled, making it rock.





So... that's why.