Which of the following terms does not refer to one of the four types of potentially infectious types of microorganisms?

A. microbes

B. pathogenic

C. nonpathogenic

D. toxins

D. toxins

Explanation:

Toxins are not microorganisms, in fact they are non-living substances/chemicals which can cause infection in our body. Toxins may be produced by microorganisms but they are themselves not microorganisms. Some of the examples of toxins produced by microorganisms are botulinum toxin A, tetanus toxin A, muscarine etc.

Other options can refer to potentially infectious type of microorganisms. Option A. talks about microbes, among microbes some are pathogenic. Option B. talks about pathogenic, as the name indicates will be infectious for sure.

Option C. talks about nonpathogenic, it may be non pathogenic at a time but later on it can be pathogenic. For example: some vaccines use inactivated microbes which are non pathogenic for generating antibodies in the body but later on in the human body when they get optimum conditions for growth they can turn pathogenic and start infecting our body.