Answer:
The human body contains trillions of cells, 78 different organs and more than 60,000 miles of blood vessels if you stretched them end-to-end. Incredibly, all of these cells, vessels and organs work together to keep you alive.
Each organ belongs to one of ten human body systems. These body systems are interconnected and dependent upon one another to function. Your heart does not beat unless your brain and nervous system tell it to do so. Your skeletal system relies on the nutrients it gains from your digestive system to build strong, healthy bones.
