After 20 years of repetitive work, even routine tasks can cause problems. As workers reach their mid-40s, the body can get a bit more brittle and can take longer to heal. By age 55, the average person has lost about XX percent of the muscle mass he or she had at age 25.
     A. 10 percent
     B. 15 percent
     C. 20 percent

Answer: B. 15 percent!