The skeletal system provides structural support for the entire body. what makes bones strong enough to protect body tissue?

Bones contain three components that in itself make it strong and flexible. They are collagen, calcium phosphate, and living bone cells. Collagen gives bones their structure, calcium makes bones strong, and cells generate more bone cells to fill up weakened parts. Calcium intake from food supplements and milk are also good for the bones because it can strengthen them more and make the skeletal system protected from bone irregularities and problems while growing. Vitamin D is essential for the absorption of calcium in bones. In order to offer support to the muscles and tissues of the body, bone growth is very crucial, because a weak bone cannot make the body function well. 

35 cubic feet of dirt if it's digging a burrow