Question

which describes a way that prevailing winds control precipitation totals in a region?
○ they cause oceanic winds to carry water vapor.
○ they force cool, moist air from oceans to rise as it moves toward land.
○ they increase the occurrence of droughts in the winter.
○ they reduce rainfall on the leeward side of a mountain.

Explanation:

To solve this, we analyze each option:

• Option 1: Oceanic winds carrying water vapor is more about wind's role in transporting moisture generally, not specifically how prevailing winds control precipitation totals in a region's leeward/ windward context.
• Option 2: Prevailing winds typically force warm, moist air (not cool) from oceans to rise over land. So this is incorrect.
• Option 3: Droughts in winter are not a direct way prevailing winds control precipitation totals in a region. Droughts are a result of lack of precipitation, not a mechanism of control.
• Option 4: Prevailing winds, when they hit a mountain, the windward side gets precipitation as air rises and cools. On the leeward side, the air descends, warms, and holds moisture, reducing rainfall. This is a key way prevailing winds control precipitation totals (creating rain shadows on leeward sides).

Answer:

D. They reduce rainfall on the leeward side of a mountain.