You are presented with the question "Crop growth can be negatively impacted by" and the following answer choices: 
- fossil fuels
 - light pollution
 - Pollution
 - drought
 - rainbow falls
 - Greenhouse gasses
 - lunar eclipse
 - air pollution

Now knowing that air pollution can cause the pH of soil to decrease and highly acid soil is detrimental to crop growth and biological activity in soil, choose the best answer.


 

        air pollution 