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

Fact 2: Soil erosion Deforestation and excessive crop irrigation enhance soil erosion.

Given the two facts above, answer the question "what and excessive crop irrigation enhance negative impacts on the environment" with the following options: 
- contamination
 - drought
 - humans disturb it
 - Pollution
 - Greenhouse gasses
 - Deforestation
 - uncontrolled
 - threatened


 

      Deforestation   