Carlos went to weight-lifting camp in the summer between seventh and eighth grade. He noticed that the trainer put tremendous pressure on participants to improve their strength. After an especially...

Carlos went to weight-lifting camp in the summer between seventh and eighth grade. He noticed that the trainer put tremendous pressure on participants to improve their strength. After an especially vigorous workout, Carlos’s arm felt extremely sore and weak around the elbow. He went to the camp doctor, who took X-ray photos and then told him that the injury was serious because the “end, or epiphysis, of his upper arm bone was starting to twist off.” What had happened? Could the same thing happen to Carlos’s 23-year-old sister, Selena, who was also starting a weight-lifting program? Why or why not?