Explain how does circulatory system finishes the work of digestive and respiratory system?

Hmm. I really do not know but probably the circulatory system helps the digestive and respiratory by sending RBC to them. Since the respiratory is related to circulatory (The Blood needs Oxygen so they go to the lungs to get some) I think thats how it finishes it's work. At Digestive I'm not really sure but probably it helps the intestines to digest much better and gives them energy from the blood. Hope this helps. Good Luck