There is no doubt that even if the bone density of adult men is hard, they can't compare with a hammer. Do not believe that you can do experiments with pig bones, but don't make fun of people, or you will bear legal responsibility. People sometimes break their bones when they fall, and the hardness of adult bones will gradually calcify with age, so the general elderly need calcium supplementation, but vitamin AD should be supplemented for calcium supplementation and absorption, otherwise calcium will not be easily absorbed by the human body. People's daily nutritional intake should be balanced, not partial eclipse, not overeating, and at the same time strengthen physical exercise to improve their immunity and resist viral infection. The human skeleton consists of 206 pieces. Don't let the skeleton get hurt easily. It is a kind of injury to hurt the muscles and bones for a hundred days.