| A | B |
|---|
| tundra | found along the Arctic coast |
| basin | large or small depression in the the land surface |
| smog | haze caused by the sun's interaction with exhaust gases |
| Appalachian Mts. | mountain chain in eastern U.S. |
| coal | natural resource found in Appalachian Mts. |
| Piedmont | area of low rolling hills east of the Appalachian Mts. |
| Mackenzie River | Canada's longest river |
| St. Lawrence Seaway | important deepwater shiping route |
| glaciers and erosion | causes of loss of height in Appalachian Mts. |
| fall line | divides Piedmont and Coastal plain |
| Mississippi River | largest river in U.S. |
| air conditioning | assisted in development of the West |
| Missouri and Ohio Rivers | tributaries of Mississippi River |
| Rio Grande River | forms border between U.S. and Mexico |
| Panama Canal | links Atlantic to Pacific Ocean |
| mesas | flat-topped elevations |
| continental divide | high ground separating rivers in Rockies that flow east and west |
| humid continental | experiences four seasons |
