Correct Response: D. Calcium and phosphorus are both needed for healthy bones. However, when there is more phosphorus than calcium in the body, calcium tends to be drawn out of bones to balance out the excess phosphorus. This can be detrimental because it makes bones weaker. Phosphorus actually helps the body use certain water-soluble vitamins, such as vitamin B (A), and certain fat- soluble vitamins, such as vitamin D (C), rather than interfere with their function and metabolism. The kidneys help regulate the concentration of phosphorus in the blood. However, the ability of the kidneys to remove excess phosphorus does not vary significantly between children and adults (B).
