Submarine terrain refers to the underwater landscape found on the ocean floor. It includes various features such as mountains, valleys, and plains, similar to those on land. The ocean floor is shaped by geological processes like tectonic activity, erosion, and sediment deposition, creating diverse environments. Key features of submarine terrain include the continental shelf, which is a shallow area near coastlines, and the mid-ocean ridge, a mountainous region formed by tectonic plate movements. Other important structures are submarine canyons, which are deep valleys cut into the ocean floor, and abyssal plains, which are flat areas found at great depths.