Fact 1: Being exposed to wind can cause erosion of soil.

Fact 2: To many people, soil is nothing but dirt.

Given the two facts above, answer the question "Being exposed to what can cause erosion of dirt?" with the following options: 
- cement
 - wind
 - deltas
 - rocks
 - rain
 - a building
 - rivers
 - cars


 

  wind       