Which mineral is the most abundant in the human body?

• A. Iron
• B. Potassium
• C. Calcium
• D. Magnesium

Answer: (C)

Calcium is the most abundant mineral in the body because the skeleton serves as a massive reservoir, storing about 1–2 kilograms of calcium. About 99% of this calcium is locked into bones and teeth as hydroxyapatite, which provides structural strength. The remaining calcium circulates in blood and within cells to support critical functions like muscle contraction, nerve signaling, and blood clotting, but this amount is small compared with what’s stored in bone. In contrast, minerals like iron, potassium, and magnesium exist in far smaller total amounts in the body, even though they are essential for many physiological processes. So the large skeletal calcium store makes calcium the most abundant mineral overall.