I studied the Immune System and it is located near your stomach and in your lungs. Also, it is in your nose and your spleen. I learned that it protects you from millions of germs everytime you breathe in. There are many organisms in your Immune System called cells. There are also other cells called macrophages. Macrophages eat germs but if the germs are alive the macrophages will not eat them. So the white blood cells will kill the germs and then let the macrophage eat it. Now, I know that the Immune System is what keeps us all healthy.