| A | B |
|---|
| Continental Margin | region of the seafloor that contains the shelf and slope |
| 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, regions made up of mountains, ridges, trenches, valleys, rifts, guyots, abyssal plains, and canyons plateau |
| Abyssal Plain | vast smooth areas on floor |
| Trenches | cracks on the earth's crust, deepest part of the oceans |
| Guyots | flat topped volcanic mountains |
| Rift | a valley that runs along the center of a ridge |
| Seamount | isolated mountain that rises mor 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 |
| Percent of the Earths Surface Covered by water | 75% |
