>>12056415If you don't lift, you likely fall into one of these categories.
These average body shapes come from your developed skeletal structure from genes, and muscles building naturally with the random monotony of life
This is why each muscle group tends to differ in size; some people barely exercise, some end up doing more outdoor work, some do a lot of running.
When you begin lifting, you strengthen and build muscle mass in a more distributed way, and can focus certain muscle groups over others in order to change your profile.
pic related, arguably an endomorph (with more muscle mass on his abs then the rest of his body) building muscle mass in his pecs, delts, lats, and traps to give a more mesomorphic appearance.
