Q: Fact 1: Amold spore has a negative impact on the respiratory system. Fact 2: Major components of the respiratory system are the lungs, trachea, nose, and the cell. Given the two facts above, what has a negative impact on the lungs?

Possible answers:
[a]. unpolluted air
[b]. healthy atmosphere
[c]. mold spore
[d]. smoking
[e]. disease
[f]. influenza
[g]. clean air
[h]. A virus
A:
[c].