Fact 1: Acid rain has a negative impact on water quality.

Fact 2: Cars and trucks emit tremendous amounts of airborne pollutants, which increase acid rain.

Given the two facts above, answer the question "Which of the following has the worst effect on water quality?" with the following options: 
- bacteria
 - Pesticides
 - fossil fuels
 - deforestation
 - cars and trucks
 - humans disturb it
 - flooding
 - Destroy bridges


 

     cars and trucks    