Fact 1: Disease-causing microbes have a negative impact on the body.

Fact 2: Microbes are microscopic, single-celled organisms without a nucleus.

Given the two facts above, answer the question "What has a negative impact on the body?" with the following options: 
- photons
 - exposure to cold
 - abundant food
 - influenza orthomyxoviruses
 - disease-causing organisms
 - smallest agents of disease
 - rocks
 - a tree falling


 

     disease-causing organisms    