Fact 1: Planting trees has a positive impact on an ecosystem.

Fact 2: Forest ecosystems, from trees to microbes, remove pollutants in a number of ways.

Given the two facts above, answer the question "What can planting trees reduce?" with the following options: 
- Pollutants
 - energy barrier
 - competition
 - temperature
 - Fire danger
 - Shade
 - Trees
 - disease


 

 Pollutants        