Answer: Capillaries pass oxygen and waste between blood and cells.
Explanation: Capillaries are very thin-walled tubes that connect the arteries to the veins. The walls of these tubes are only one cell thick. Capillaries are found everywhere in the body. These thin tubes allow the food, oxygen, and waste to move between the bloodstream and cells. Waste products pass into capillaries and are carried by the veins to be disposed of in other parts of the body. Capillaries are the only blood vessels thin enough for materials to pass back and forth between cells and blood.
