B. Bone denesity because as we age our bones become brittle and can break easily hence why older people often break their wrist or hips when falling. And being fit can help.
Studies show that the frequent decline in bone density that happens during aging can be slowed with regular physical activity.
The exercise is highly recommended to people with osteoporosis, the exercise stimulates extra deposits of calcium and bone-forming cells, some of the benefits of exercising for the bones are reduce the bone loss, preservation of the bone tissue, increase the muscle strength, reduce the risk of bone fractures. The answer is B.
