What is the system through which the blood moves? What is the food for the cells?
The circulatory system is the collective mass of arteries, capillaries, and veins that spread throughout your entire body so that oxygen may be delivered to tissues that need it. This process of "circulation" is all driven by the heart.
The red blood cells are the major transporters of oxygen in the circulatory system. Because they are transporting oxygen for other tissues to use, they survive on a strict diet of glucose, which they absorb directly from the blood. They dump any waste materials back into the blood, where they are picked up by the liver and recycled into more glucose. This process is known as the Cori cycle, which can be seen in the diagram below:
Hope this helps!