The Reason That Treelines at the Same Latitudes North and South

Multiple Choice

The reason that treelines at the same latitudes north and south of the Equator occur at different altitudes is ________.

A) the varying solar radiation received by each hemisphere
B) that there are few mountains in the Southern Hemisphere
C) the Sun is usually higher in the sky in the Northern Hemisphere
D) that there is more ocean in the Southern Hemisphere
E) not completely understood