Final answer:
Erythropoietin (EPO) is an example of a cytokine that also functions as a hormone, primarily involved in the production of red blood cells.
Step-by-step explanation:
Cytokines are protein molecules that act as chemical signals and are critical for cell communication, especially within the immune system. An example of a cytokine that also functions as a hormone is Erythropoietin (EPO), which is produced by the kidneys and stimulates the production of red blood cells in the bone marrow.
While cytokines like Interleukins and Colony-Stimulating Factors (CSFs) primarily regulate immune responses and hematopoiesis, EPO has the dual role of acting as a systemic hormone, regulating red blood cell production, and is used medically to treat certain anemias.