Final answer:
Erythropoietin is a hormone produced by the kidneys that stimulates red blood cell production.
Step-by-step explanation:
Erythropoietin (EPO) is a hormone produced by the kidneys that stimulates the production of red blood cells.
When the kidneys detect low oxygen levels in the blood, they release EPO, which then signals the bone marrow to produce more red blood cells. EPO is essential for maintaining adequate oxygen supply in the body.