The digestive system and the skeletal system work together because the bones form protection so nothing falls out or anything of that matter.
The muscular system and the skeletal system all work together because if the bones did not have the muscle, then we would not be able to walk, or even run. Those are all of the things that we do in all of our dailly scheduals.
The resperitory system and the skeletal system work together because without this, if we ran we would not be able to breath AT ALL. Without breathing you would die, trust me!