The least important system in the body is arguably the scalp hair. It only serves as a means to look good and to attract the other sex.
Really, everything in your body plays an important role.
An individual person does not have to reproduce in order to survive, but the species only continues to exist if reproduction takes place.
The most important system in the upper and lower body is the Circultory System
The metatarsals
immune system
Your hair.
The appendix.
Respiration
It helps people survive and live a normal life.
The hagoo system
it is important because your thing is cool
the nerve system is important b/c it controls all the thins in the body!!!!!!!