15. The circulatory and respiratory systems work together to provide cells with oxygen and nutrients and remove wastes such as carbon dioxide. When the body needs more oxygen how does the circulatory system respond? A. The heart beats faster to match the increase in breathing rate. B. More blood is sent to the lungs and less to the rest of the body. C. The blood vessels in the arms and legs constrict to conserve oxygen D. Blood moves more slowly through the organs to carry away more wastes 16. What happens in the diaphragm when we exhale (breathe out)? A. The diaphragm relaxes and moves upwards. B. The diaphragm contracts and moves upwards. C. The diaphragm relaxes and moves downwards. D. The diaphragm contracts and moves downwards 17. Are the smallest blood vessels that move blood to and from the cells of the body A. veins B. capillaries C. arteries D. ventricles 18. its main function is to keep the blood moving constantly through the body. A. alveoli B. bronchioles C. heart D. lungs 19. What will happen if the epiglottis does not close the entrance of airways? A. The larynx will be blocked with food particles B. The pharynx will have difficulty in swallowing C. The food partides will block the opening of the trachea and a person will have difficulty in breathing D. The food particles will block the bronchioles thus making it difficult to breathe in and breathe out 20. Which is NOT a function of the circulatory system? A. Deliver oxygen and nutrients to cells B. Break down carbohydrates into glucose C. Transport other materials through body D. Remove carbon dioxide and wastes from cells​