conclusion
skeletal and muscular system
The skeletal and muscular system work together very closely to help make the body move. Without one, the other would not be able to function. If the skeletal system did not supply structure to the body there would be nothing for the muscles to cling on to and move the part of the body. And if the muscles weren't there the bone would not be able to lift up the limb and make a movement. The muscles and bones also help to provide protection to the other systems in the body.
respiratory and circulatory system
Similarly to the skeletal and muscular system, the circulatory and respiratory system work together to do a job- but this time it is oxygenating the body. For the body to function it needs to have a constant supply of oxygenated blood and a way to dispose of the used, deoxygenated blood. It does this by the heart and lungs working as one to oxygenate and transport blood around the body and brain. The lungs inhale oxygen from the air and it passes through the capillaries and alveoli into the blood stream, which returns to the heart via the pulmonary vein and gets pumped around the body. They also take in the used blood and send the co2 out out of the body by exhalation. Before this unit whenever someone had mentioned supplying the body with blood I would think of the heart automatically, but now i understand that the lungs and heart play an equal role.