Unequal heating of Earth 's surface by the Sun causes global wind patterns, and another major type of wind is called a polar easterly. Given these facts, unequal heating of Earth 's surface by what causes polar easterlies among the following options:
- sun
 - UV
 - drag
 - wind
 - loch
 - ovens
 - lightbulbs
 - blankets


 

 sun        