| A | B |
|---|
| global ocean | saltwater covering 75% of Earth's surface |
| sonar | sound waves used to determine distance |
| trench | deepest v-shaped area on ocean floor |
| abyssal plain | flattest part of ocean floor |
| nodule | mineral lump on ocean floor |
| continental shelf | flat area next to all continents |
| continental slope | steep dropoff on ocean floor |
| guyot | flat topped mountain on ocean floor |
