Which Substance is Not a Known Carcinogen

Question

Which substance is not a known carcinogen?
A) certain viruses
B) ultraviolet light
C) cigarette smoke
D) pet dander

Accepted Answer

Pet dander is not a known carcinogen. A carcinogen is a substance or agent that has the potential to cause cancer. Certain viruses, ultraviolet light, and cigarette smoke are all known carcinogens.