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

Fact 2: Air-mass boundaries are generally associated with frontal zones.

Given the two facts above, answer the question "the movement what over Earth 's surface causes local weather changes" with the following options: 
- lava
 - Temperature
 - moon
 - frontal zones
 - global warming
 - kinetic energy
 - The atmosphere
 - animals


 

    frontal zones     