You are presented with the question "What has a negative impact on water quality?" and the following answer choices: 
- Reverse osmosis
 - fossil fuels
 - Fresh water
 - Carbon filter
 - chlorofluorocarbons
 - Sulfur dioxide
 - Pollution
 - harmful substances

Now knowing that acid rain has a negative impact on water quality and sulfur dioxide causes acid rain, choose the best answer.


 

      Sulfur dioxide   