In your analogy, oil refineries and chemical plants would be more like the digestive system, that breaks raw substances down to useable energy units that power things like blood cells and the muscle cells that make up the heart to pump the blood throughout the body. Bone marrow would be more like semi truck factories that build new trucks in order to keep the supply up and replace any old ones that broke down over time.
In your analogy, oil refineries and chemical plants would be more like the digestive system, that breaks raw substances down to useable energy units that power things like blood cells and the muscle cells that make up the heart to pump the blood throughout the body. Bone marrow would be more like semi truck factories that build new trucks in order to keep the supply up and replace any old ones that broke down over time.
Very good build on the analogy! Nailed it perfectly!