Fact 1: Smoking causes direct damage to the lungs.

Fact 2: When lung damage is experienced, frequently the total capacity of the respiratory system is reduced.

Given the two facts above, answer the question "What can reduce respiratory system capacity?" with the following options: 
- Breathing
 - Smoking
 - influenza
 - bacteria
 - Pollution
 - Exercising
 - Pesticides
 - Singing


 

  Smoking       