What are the 2 major groups of muscles

The major skeletal muscle groups forming the upper body are the abdominal, pectoral, deltoid, trapezius, latissimus dorsi, erector spinae, biceps, and triceps. The major skeletal muscle groups of the lower body are the quadriceps, hamstrings, gastrocnemius, soleus, and gluteus.

Ican only answer your first question, a machine is like a human body because it's a little similar. they both almost work like the same.