| A | B |
|---|
| Continental Divide | an imaginary line that seperates rivers flowing eastward and westward across the land |
| erosion | the gradual wearing down of the earth's surface by water and wind |
| temperate | neither too hot nor too cold |
| timberline | the elevation above which trees cannot grow |
| arable | good for farming |
| population density | people per square mile in a given land area |
| permafrost | a layer of soil that is permentaly frozen |
| hydroelectric power | electricity generated by the force of rapidly moving water |
