| A | B |
| continental margin | region of the sea floor that contains the shelf an dslope |
| continental shelf | part of the continent that is underwater |
| continental slope | where water deepens abruptly and the edge of the continental land mass drops off |
| ocean basin floor | begins where the slope ends, region made up of mountains, ridges, trenches, valleys, rifts, guyouts, abyssal plains, and canyons plateau |
| abyssal plain | vast smooth areas on the sea floor |
| trenches | crack's on the earth's crust, deepest part of the oceans |
| guyouts | flat topped volcanic mountains |
| rift | a valley that runs along the center of a ridge |
| seamount | isolated mountain that rises more than 3,000 ft. above the sea floor |
| mid-ocean ridge | great undersea mountain ranges characterized by frequent earthquakes and volcanoes |
| island | seamount that rises above the surface of the water |