| A | B |
| arroyo | small river in a dry area |
| biome | major community of interdependent plants, animals, and land features |
| climates | normal weather patterns |
| environments | conditions under which plants and animals can live |
| evaporates | changes from liquid to gas |
| mouth | where a river empties into a lake or ocean |
| percent | one one-hundredth of something |
| sources | places where rivers start |
| spring | water coming from the ground that begins a river |
| tributaries | small rivers that enter a larger river |