| A | B |
|---|
| resource | material that people use |
| sodium chloride | table salt |
| nodule | lump of metals found on the ocean floor |
| petroleum | liquid fuel made from living things that lived millions of years ago |
| current | a river of water that flows through the ocean |
| tide | the rise and fall of the surface level of the ocean |
| crest | the highest point of a wave |
| trough | the lowest point of a wave |
| wave height | distance between the crest and the trough |
| continental shelf | the shallow part of the ocean floor close to the edge of the continent |
| continental slope | the land from the continental shelf to the ocean basin |
| ocean basin | the deep ocean floor |
| trench | a deep narrow valley in the ocean floor |
| ridge | a chain of underwater mountains |
| oceanographer | scientist who studies the ocean |
