Fact 1: Cutting down trees has a negative impact on an ecosystem.

Fact 2: An example is the uncontrolled cutting of trees for fuel.

Given the two facts above, answer the question " uncontrolled use of what for fuel has a negative impact on an ecosystem" with the following options: 
- trees
 - oil
 - deserts
 - habitat
 - solar
 - air
 - coal
 - rocks


 

 trees        