That's an interesting question! The human body is made up of many biological systems, which are themselves made from groups of specialized tissues and organs, that work together to form and maintain a human's life. You are probably familiar with some of these systems that together make a human body.

The systems that make the human body include the: digestive system (which processes food through organs including the mouth, stomach, and intestines); circulatory system (which includes the heart, blood, vessels and arteries that are necessary for moving oxygen, nutrients, and waste); nervous system (which includes the brain, spinal cord and nerves that send signals through the body); respiratory system (for exchanging oxygen and carbon dioxide - a waste product - when you inhale and exhale through your nose, trachea, and lungs); skeletal system (bones, cartilage, tendons and ligaments that give the body physical support and are where muscles attach); and the muscular system (which include skeletal muscles, which produce voluntary movement, and smooth muscles, which produce involuntary movement, like the beating of your heart).