Instead of using animals in medical expereince, i think<< that scientests could test it on bacteria or humans, if it is safe enough.
I believe 7% is almost correct because most people can try to quit smoking a year but hardly ever succeed
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!
