The soluble products of the digestive system (i.e.glucose) are moved into the circulatory system and transported to organs to perform a function (i.e. muscles for respiration)
Answer:
because you are using them and it because it your bones get tired
Answer: The circulatory system provides your brain with a constant supply of oxygen-rich blood while your brain regulates your heart rate and blood pressure. Even seemingly unrelated body systems are connected.
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