What is a primary function of lymphocytes?

Lymphocytes are a vital component of the immune system, and their primary function is to act against foreign substances, such as pathogens and cancer cells. These white blood cells play a crucial role in identifying and responding to invaders by recognizing specific antigens. There are different types of lymphocytes, including B cells and T cells, that carry out distinct functions. B cells are responsible for producing antibodies, which bind to antigens and neutralize pathogens, while T cells can directly kill infected cells or help coordinate the immune response.

This function is essential for the body's ability to protect itself from infections and diseases. By identifying and targeting foreign substances, lymphocytes can help maintain health and contribute to the overall immune response. Other options such as producing hormones, transporting oxygen, and maintaining fluid balance represent functions associated with different cells and systems in the body, but they do not align with the primary role of lymphocytes in immune defense.