What is the role of B and T cells in the immune system?

B and T cells are integral components of the adaptive immune system, which is responsible for recognizing and responding to specific pathogens. B cells are primarily involved in the humoral immune response, where they produce antibodies that bind to antigens on pathogens, neutralizing them or marking them for destruction by other immune cells. T cells, on the other hand, play a crucial role in cell-mediated immunity, recognizing infected cells, and orchestrating the immune response through the release of cytokines and cytotoxic activity.

This adaptive response is characterized by its ability to remember specific pathogens after an initial exposure, resulting in a faster and more effective response upon subsequent encounters with the same pathogen. This aspect distinguishes adaptive immunity from innate immunity, which provides immediate but non-specific defense.

In contrast, transporting oxygen in the blood is primarily the function of red blood cells, forming barriers against pathogens is a role of physical structures such as skin and mucosal membranes, and producing hormones for growth relates to the endocrine system rather than the immune system. Thus, the role of B and T cells is specifically tied to mediating adaptive immune responses, which makes this choice the most accurate reflection of their function in the immune system.