Which of the following describes the two types of immune responses?

The two main types of immune responses are the humoral immune response and the cell-mediated immune response.

The humoral immune response is primarily mediated by B cells and the antibodies they produce. When B cells encounter a specific antigen, they differentiate into plasma cells that secrete antibodies. These antibodies circulate in the bloodstream and lymphatic system, binding to antigens and neutralizing pathogens or marking them for destruction by other immune cells.

In contrast, the cell-mediated immune response involves T cells, which play a critical role in defending against intracellular pathogens such as viruses and some bacteria. T cells can directly kill infected cells, help activate other immune cells, and regulate the immune response. This response is essential for eliminating infected or cancerous cells from the body.

Other options include different combinations of immune response types that do not accurately characterize the two principal categories of adaptive immunity. For example, innate immune responses provide a first line of defense against pathogens but are not specific and do not have the memory characteristic of adaptive immune responses.