the answer is smooth muscles
The least likely explanation for this would be that they're training at different intervals, or one is training harder than the other.
The most likely reason is that the way the other person's genetics are most people cant gain muscle as well as others because of disease or their body structure.
Hope this helped!
I would help u write an essay but there gotta be more points
1.respiration
2.diaphragm
3.lungs
4.inhaling
5.out
6.
7.i think trachea
8.rib cage
not sure for 3 and 6 cuz diagram is needed
