| A | B |
|---|
| canyon | deep, narrow valley with steep sides |
| coastal plain | area of flat land along a sea or ocean |
| delta | triangle-shaped area of land at the mouth of a river |
| isthmus | narrow strip of land connecting two larger areas of land |
| mouth of river | place where a river empties into another body of water |
| peninsula | land that is almost completely surrounded by water |
| plains | areas of flat or gently rolling land |
| sea level | level of the surface of an ocean or a sea |
| source of river | place where a river begins |
| tributary | stream or river that flows into a larger stream or river |
