The (human) body has 12 different systems, namely
1. skeletal system
2. Nervous system
3. Integumentary system
4. Cardiovascular/circulatory system
5. Endocrine system
6. Muscular system
7. Respiratory system
8. Excretory system
9. Reproductive system
10. Digestive system
11. Immune / Lymphatic system
12. Urinary system.
Of these, it is the cardiovascular/circulatory system that transports oxygen and nutrients to all parts of the body while taking away metabolic waste thus enabling all body parts from cells to complex organs maintain homeostasis.