| A | B |
|---|
| till | the mixture of soil and rocks that covers much of Ohio |
| natural resource | something found in the environment that people can use |
| glacier | a huge sheet of ice that moves slowly across the land |
| Ice Age | a period of time when glaciers covered much of Earth's surface |
| transportation | the moving of goods or people from one place to another |
| barge | huge flat boats used to carry goods on rivers |
| source | the place where a river begins |
| mouth | the place where a river empties into an ocean or another large body of water |
| tributary | any river that flows into another, larger river |
| river basin | all the land drained by a river and the river's tribuatries |
| port | a place where ships load and unload their goods |
| pollution | result of carelessly using resources, such as chemicals, that make air, water, or soil dirty |
