Final answer:
During early adolescence, boys tend to gain muscle while girls gain body fat.
Step-by-step explanation:
During early adolescence, boys tend to gain muscle while girls gain body fat. This is due to the differences in hormonal changes and the process of puberty. In males, testosterone promotes muscle growth and development, leading to increased strength and muscle mass. On the other hand, females experience hormonal changes that result in the deposition of body fat, especially in areas like the breasts and hips.