What affects the respiratory and circulatory systems in the body?
Options:
- (A) HIV
- (B) sulfur
- (C) smog
- (D) stress
- (E) fever
- (F) sweat
- (G) heat
- (H) tar OK. Let's think hard:
Air pollution harms the respiratory and circulatory systems. An example of an air pollution reaction is the production of photochemical smog. Smog harms the respiratory and circulatory systems.
So, the final answer is (C).