OPTIONS:
[I] sun;
[II] UV;
[III] drag;
[IV] wind;
[V] loch;
[VI] ovens;
[VII] lightbulbs;
[VIII] blankets;

Fact 1: Unequal heating of Earth 's surface by the Sun causes global wind patterns. Fact 2: Another major type of wind is called a polar easterly. Given the two facts above, unequal heating of Earth 's surface by what causes polar easterlies?
Answer:
[I]