You are presented with the question "What causes damage to forest ecosystems?" and the following answer choices: 
- flooding
 - humans disturb it
 - Sulfur dioxide
 - deforestation
 - Liquid bromine
 - Carnivore animals
 - Pollution
 - Hydrogen peroxide

Now knowing that the emission of sulfur dioxide causes acid rain and acid rain effects forest ecosystems, choose the best answer.


 

   Sulfur dioxide      