Outline the role of calcium in the body and factors affecting its bioavailability.

• A. Calcium supports bone and teeth, nerve conduction, and muscle contraction; bioavailability is influenced by vitamin D status, oxalates, phytates, and age.
• B. Calcium only affects bone density and has no role in nerve signaling.
• C. Calcium absorption is not affected by dietary factors.
• D. Calcium is only stored in the liver and not used in bones.

Answer: (A)