Fact 1: Erosion of soil has a negative impact on the environment.

Fact 2: Dirt is really misplaced soil.

Given the two facts above, answer the question "What usually has a negative impact on the environment?" with the following options: 
- cigarettes
 - humans disturb it
 - harmful substances
 - sunlight
 - deforestation
 - erosion of dirt
 - rainfall
 - moon phases


 

      erosion of dirt   