Chapter 19 Bacteria and Viruses. Remember homeostasis? Maintaining proper internal conditions pH, temp., water/salt balance, O2, CO2, etc.
What Causes Disease? Germ Theory of Disease: –Developed by Louis Pasteur and Robert Koch Infectious diseases occur when microorganisms cause changes that.
32-1 © 2009 The McGraw-Hill Companies, Inc. All rights reserved Defenses Against Disease Infection The presence of a pathogen in or on the body Pathogen.
