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

Fact 2: Soil Erosion Soil erosion is a natural process.

Given the two facts above, answer the question "What kind of process can have a negative impact on an environment?" with the following options: 
- coal
 - natural
 - Pesticides
 - flooding
 - cigarettes
 - Smoking
 - Cars
 - burning


 

  natural       