Which organ filters blood, recycles iron, and fights infections?

• A. Liver
• B. Cervix
• C. Pancreas
• D. Spleen

Answer: (D)

The spleen acts as a blood filter and an immune organ. It has red pulp that removes aging red blood cells and, in the process, macrophages recycle iron from hemoglobin back into the body. At the same time, its white pulp is rich in lymphocytes and other immune cells that detect and respond to pathogens in the bloodstream, helping to fight infections. This combination—filtering blood, recycling iron from hemoglobin, and supporting immune defense—fits the spleen best. The liver does participate in iron handling and immune functions but is not primarily the organ described here; the cervix is part of the reproductive tract, and the pancreas mainly handles digestion and blood sugar regulation.