Is the muscular system diffrent from a girl and boy

The muscle system for a boy and a girl are the same. They can perform and respond in the same manner. The difference only occurs in the development of muscle mass, where men can develop more muscle mass than female. This difference is brought by the type of activities that the two sexes engage in. Muscle group development can be altered by a person’s current exercise program and way of life.

a- all cells come from pre-existing cells

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.