Fact 1: Viruses cannot reproduce by themselves.

Fact 2: Influenza is a disease caused by viruses.

Given the two facts above, answer the question "Which of these diseases cannot reproduce by itself?" with the following options: 
- fever
 - Leptospirosis
 - animals
 - influenza
 - bacteria
 - heat or cold
 - dangerous
 - anemia


 

    influenza     