Fact 1: Viruses cannot reproduce by themselves.

Fact 2: Examples include influenza, rabies, HIV, and Herpes viruses.

Given the two facts above, answer the question "what cannot reproduce by themselves?" with the following options: 
- acid rain
 - bacteria
 - ferns
 - fungi
 - mammals
 - goats
 - rabies
 - insects


 

       rabies  