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

Fact 2: When ecosystems are healthy, humankind is healthy.

Given the two facts above, answer the question "cutting down trees has a negative impact on the health of what?" with the following options: 
- space
 - humankind
 - mars
 - aliens
 - salmon
 - Species
 - humans
 - plants


 

  humankind       