Perforin is a molecule released by natural killer cells to create holes in the plasma membrane of a virus infected cell.

Choose the answer that has word(s) in the correct order to fill in the blanks producing a true statement. COVID-19 was originally classified as a(an) ________________ disease and is now classified as a(an) _______________ disease?

Bacteriostatic agents prevent bacteria from growing but do not kill the bacterial

 Which of the following is a protective viral cytopathic effect?

Which cell, in the the process of clonal selection, recognizes antigen presented on B-cells, then secretes cytokines to cause that B-cell to proliferate and differentiate?

A sign is a subjective symptom.

How is antigen presented on the surface of an antigen presenting cell?

According to the instructor, the CEO of a large airline took extreme cost-cutting measures to save money that included what?

Which choice is/are chemical factor(s) in the first line of defense?

Which of the following exotoxin types is responsible for red blood cell hemolysis seen as alpha and beta hemolysis on blood agar plates?