You are presented with the question "Which type of pollution is most harmful to lungs?" and the following answer choices: 
- Lead
 - air
 - Cars
 - oil
 - acid
 - CFCs
 - SO2
 - mold

Now knowing that air pollution harms the respiratory and circulatory systems and exposure to ozone can diminish lung function and increase susceptibility to respiratory infection, choose the best answer.


 

  air       