Why Are Koch's Postulates Important to Microbiology

Why are Koch's postulates important to microbiology?

A) They enable us to characterize the species of the infectious disease whether it is a bacteria, virus, or fungi.
B) They provide a way to select the most effective concentration of antibiotic to use for a patient.
C) They demonstrate the preferred route of infection for a particular disease.
D) They allowed us to identify the causative pathogens of many infectious diseases.
E) They explain how a particular disease produces specified signs in a patient.