What is the underwater volcanic mountains that divide ocean floor into two parts?

The underwater volcanic mountains that divide the ocean floor into two parts are called mid-ocean ridges. These ridges are formed by the process of seafloor spreading, where new oceanic crust is created at the boundaries of tectonic plates. As the plates move apart, magma rises from the mantle and erupts onto the ocean floor, forming new crust. This process creates a continuous chain of underwater mountains that can stretch for thousands of kilometers. The mid-ocean ridges are also home to hydrothermal vents, which are formed when seawater seeps into the cracks in the ocean floor and is heated by the Earth's internal heat. These vents spew out hot water and minerals, creating a unique ecosystem that supports a variety of marine life.