You are presented with the question "What can reduce respiratory system capacity?" and the following answer choices: 
- Breathing
 - Smoking
 - influenza
 - bacteria
 - Pollution
 - Exercising
 - Pesticides
 - Singing

Now knowing that smoking causes direct damage to the lungs and when lung damage is experienced, frequently the total capacity of the respiratory system is reduced, choose the best answer.


 

  Smoking       