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

Fact 2: Plants include trees.

Given the two facts above, answer the question "Doing what to plants has a negative impact on the ecosystem?" with the following options: 
- planting them
 - deforestation
 - cutting them down
 - Pesticides
 - watering them
 - massive damage
 - sitting under them
 - Abnormal cell growth


 

   cutting them down      