You are presented with the question "Which of the following has the worst effect on water quality?" and the following answer choices: 
- bacteria
 - Pesticides
 - fossil fuels
 - deforestation
 - cars and trucks
 - humans disturb it
 - flooding
 - Destroy bridges

Now knowing that acid rain has a negative impact on water quality and cars and trucks emit tremendous amounts of airborne pollutants, which increase acid rain, choose the best answer.


 

     cars and trucks    