Fact 1: Viruses infect and live inside the cells of living organisms.

Fact 2: An infection is an illness caused by the invasion of a virus or microorganism.

Given the two facts above, answer the question "Microorganisms cause what inside of the cells of living organisms?" with the following options: 
- heat
 - harm them
 - health
 - worms
 - illness
 - resistance
 - Allergies
 - antibodies


 

     illness    