Which mineral is found in every cell and supports healthy bones and teeth and normal acid-base balance?

• A. Selenium
• B. Phosphorus
• C. Calcium
• D. Iodine

Answer: (C)

Calcium carries multiple essential roles that fit this description. It’s the major mineral in bones and teeth, giving them their strength and structure. But calcium also functions inside most cells as Ca2+ ions that act as important signaling messengers, helping regulate processes such as muscle contraction, nerve function, and enzyme activity. This broad cellular role explains why calcium is found in every cell. In addition, calcium contributes to normal acid-base balance by participating in buffering systems and by serving as part of the mineral reservoir in bone that helps keep blood pH stable when needed. While other minerals also have important jobs—selenium as an antioxidant, iodine for thyroid hormones, and phosphorus for energy molecules and genetic material—the combination of bone-building power, universal cellular signaling, and involvement in pH balance makes calcium the best fit for this description.