The Wind's Speed Generally Increases with Height Above Earth's Surface

Multiple Choice

The wind's speed generally increases with height above Earth's surface because ____.

A) only the lowest layer of air rotates with Earth
B) air temperature normally decreases with height
C) wind instruments are not accurate at Earth's surface
D) friction with Earth's surface slows the air near the ground
E) air parcels expand and become less dense as they rise above the surface