Fact 1: Air pollution harms the respiratory and circulatory systems.

Fact 2: Air pollutants are inhaled.

Given the two facts above, answer the question "What system does inhaled pollution harm?" with the following options: 
- health
 - humans
 - the environment
 - circulatory
 - people
 - bones
 - lymphatic
 - cell wall


 

    circulatory     