Final answer:
The incorrect match is c. Helper T cells do not kill pathogen-infected cells; instead, they aid the immune response by releasing cytokines.
Step-by-step explanation:
a. Antigen: a foreign substance of many different types
b. BCRs: immunoglobulins
c. Helper T cell: kills pathogen-infected cells (matched incorrectly)
d. Plasma cell: involved in antibody secretion
e. T-cell activation: cell division and differentiation are both observed
The incorrect match is c. Helper T cell: kills pathogen-infected cells. In fact, helper T cells do not kill pathogen-infected cells; they stimulate other immune cells by releasing cytokines, while cytotoxic T cells are responsible for the killing of infected cells.