We work together to provide oxygen for you and your cells and to remove harmful gases like carbon dioxide.
Thanos wants to destroy all the systems in the human body, but we need to persuade him that we should be spared
The circulatory system is definantly needed! They help pump blood throughout the body, and without them, the heart can't do it's job, and you can die. Not only does it pump blood, but it also carries essential nutrients to the rest of the body. It also helps protect the body and regulate your body temperature. I bet Thanos will spare us both after he reads this !
The other systems can't survive without us because their cells need us to provide oxygen for them. Without it, they will die.
There is another system that should be spared as well. I mean, we can't be the only system left because there are other systems that do very important things that we can't.