The main substance in a human body's bones is calcium phosphate, a mineral that gives bones their strength and rigidity. About 70% of bone mass is made up of this mineral, while the remaining composition includes collagen and various proteins that contribute to bone structure and flexibility. The calcium phosphate in bones plays a vital role in maintaining overall body health and facilitating mineral deposition in the skeletal system. Adequate intake of calcium and other nutrients such as vitamin D is essential for bone health and development throughout an individual's life.