| A | B |
|---|
| history | study of the past |
| political boundary | boundary line made by people |
| latitude lines | measure the distance north and south of the Equator |
| grid | system of boxes on a map |
| region | an area that has something special about it |
| precipitation | moisture that falls from the earth |
| humidity | amount of moisture in the air |
| natural resources | things made by nature that are useful to people |
| river system | a group of streams and smaller rivers that flow into a larger river |
| climate | weather a place has over a long period of time |
| natural boundary | boundary line made by nature, such as a river or mountain range |
