Which term describes a disease-causing organism?

• A. Beneficial Microbe
• B. Disease-Causing Organism
• C. Immune Cell
• D. Enzyme

Answer: (B)

Disease-causing organisms are called pathogens. A pathogen is any microbe—bacteria, viruses, fungi, or parasites—that has the ability to invade a host, multiply, and cause illness or disease. Many microbes are harmless or beneficial, supporting digestion, vitamin production, or immune system training. An immune cell is a component of the body's defense, not a microbe. An enzyme is a protein that speeds up chemical reactions; it is not a living organism and does not itself cause disease. So the term that best describes a disease-causing organism is the one that labels the organism as a pathogen.