Final answer:
B cells are fundamental to the adaptive immune system, specifically involved in antibody-mediated immunity, or humoral immunity, by producing antibodies against specific antigens. They do not contribute to cell-mediated immunity, which is the role of T cells. The correct match for B cells is 'b. antibody-mediated immunity'.
Step-by-step explanation:
Understanding Immunity and B Cells
When matching the appropriate characteristic with the type of immunity for B cells, we must identify the correct form of immunity involved. B cells play a crucial role in the adaptive immune system. They are responsible for antibody-mediated immunity, also known as humoral immunity. B cells function by recognizing specific antigens presented by invading pathogens and responding by producing antibodies. These antibodies then tag pathogens for destruction or neutralization.
Cell-mediated immunity, on the other hand, involves T cells, which directly attack infected or altered cells, such as those infected by viruses or transformed into cancer cells. T cells orchestrate the cellular arm of the adaptive immune system and do not produce antibodies.
In contrast, innate immunity is the body's first line of defense and operates independently of antigen recognition, providing a nonspecific response to pathogens through barriers, cells, and molecules that respond the same way to all pathogens.
As for B cells, they fall under the category of antibody-mediated immunity. Therefore, the correct option is 'b. antibody-mediated immunity', as B cells are primarily responsible for this aspect of the immune response.