Fact 1: The movement of an air mass over Earth 's surface causes local weather changes.

Fact 2: Altitude and weather systems can change the air's pressure.

Given the two facts above, answer the question "What does air movement cause around the earth?" with the following options: 
- air pressure
 - waterfalls
 - Temperature
 - scattered light
 - waste products
 - global warming
 - friction
 - puddles


 

 air pressure        