It is B) because teenagers brains are still growing.
The answer should be
B) physical activity
<span>A is the correct answer. Body composition is the percentage of fat compared to the percentage of bone, muscle and water in a person's body. Medical problems can influence a person's diet and exercise habits and their metabolism, and they can cause unhealthy body compositions, for example, thyroid problems. However, medical problems rarely improve one's body composition.</span>