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The blood in
the transport system by which oxygen and nutrients reach the body's cells,
and waste materials are carried away. The heart, a muscular organ,
positioned behind the ribcage and between the lungs, is the pump that
keeps this system moving. |
Food provides us with fuel to live, energy to work and
play and the raw materials to build new cells. All the different varieties
of food we eat are broken down by our digestive system. |