Which organ filters blood, recycles iron, and helps fight infections?

• A. Gall Bladder
• B. Liver
• C. Kidneys
• D. Spleen

Answer: (D)

Think of the spleen as the blood-filtering and immune organ. Its red pulp cleanses the bloodstream by removing old or damaged red blood cells, and in doing so it salvages iron from hemoglobin for reuse in making new red cells. Its white pulp houses lymphocytes, giving it a key role in immune defense against pathogens circulating in the blood. So the spleen naturally handles all three tasks—filtering blood, recycling iron, and aiding infection defense—with the others playing only parts of the picture in different contexts (the liver, while involved in iron metabolism and immunity, isn’t the primary blood filter; kidneys filter wastes; gallbladder stores bile).