Oxygen is an invisible gas without taste or smell. It does not burn but things burn in it. It is necessary,
in order to oxidize (or burn) the food taken into the body so that the supply of bodily energy and heat may be
maintained. It is taken into the body through the lungs. Oxygen in the air breathed in passes through the
lung tissue to the blood* It also serves the purpose of a purifying agent, by combining with poisonous organic
matter in the blood.
