An individual who has little resistance to an infectious microbe is referred to as a susceptible what?

The correct term for an individual who has little resistance to an infectious microbe is a "host." In the context of infectious diseases, a host refers to an organism that can be infected by a pathogen, such as bacteria, viruses, or fungi. A susceptible host lacks the necessary immunity or defense mechanisms to effectively combat the pathogen, making it easier for the microbe to establish an infection.

In infectious disease terminology, "carrier" refers to a person or animal that harbors a pathogen and can transmit it to others, often without showing symptoms themselves. "Pathogen" is the actual microorganism that can cause disease, while "antigen" refers to a substance that triggers an immune response, specifically the production of antibodies. Understanding these definitions clarifies why "host" is the most appropriate term in this context.