The seabed (also known as the seafloor, sea floor, or ocean floor)'s the bottom of the ocean. At the bottom of the continental slope's the continental rise, which's caused by sediment cascading down the continental slope. The seabed has been explored by submersibles such as Alvin and, to some extent, scuba divers with special apparatuses. The process that continually adds new material to the ocean floor's seafloor spreading and the continental slope.… (More on Seabed)