Which of the following is not a reason people are able to avoid infection most of the time? 

A. The majority of microorganisms are either beneficial or harmless.
B. Conditions must be favorable for a pathogen to be transmitted to a susceptible person.
C. The human body has a variety of defenses against infection.
D. Pathogens comprise only a small portion of the microorganisms in a given environment.
E. Pathogens have developed ways to evade the host defenses.

E. Pathogens have developed ways to evade the host defenses.
Successful pathogens have developed ways to evade host defenses to infect the host (person) and cause disease.