Which term is defined as fungi, bacteria and mites?

• A. External parasites
• B. Contagions
• C. Pediculosis
• D. Immunity

Answer: (B)

Understanding how disease-causing agents are described in terms of transmission helps here. The word that fits fungi, bacteria and mites as agents that can cause disease and spread between people or via contaminated items is contagions. It’s a broad label for infectious agents that can be transmitted, not limited to organisms living on a host. External parasites describe organisms that live on the surface of the body, like some mites or lice, but that category doesn’t cover bacteria and fungi. Pediculosis is specifically a lice infestation, not a general category of disease-causing agents. Immunity refers to the body’s defense against disease, not the agents themselves. So contagions is the best fit.