| A | B |
|---|
| ocean trench | a long narrow slit in the ocean floor that resembles a canyon |
| seamounts | large volcanoes rising out of the seafloor. |
| seafloor plains | large regions of the seafloor that appear flat |
| continental shelf | the gently sloping edge of the continent that is covered by ocean water |
| continental slope | starts at the continental shelf and slopes down to the deep ocean floor |
| mid-ocean ridge | a long mountain chain that runs along the ocean floor |
| submersibles | underwater boats with their own power |
| sonar | used to measure features on the ocean bottom |
| volcanoes | formed many features on the ocean floor |
| bathyscaphes | underwater exploration machines operated by remote control |
| bioluminescence | the generation of light by organisms |
| oceanographers | scientists who study the ocean |
| Alvin | a submersible used to carry people to the bottom of the ocean to explore: used to explore the wreckage of the Titanic |
| air | something underwater exploration equipment must supply |
| pressure | something underwater exploration equipment must protect against |
