The gas that makes up almost ¼ of the air’s surrounding of the
earth is the oxygen. Earth atmosphere’s contains around 20.95%. Oxygen is a
chemical substance with a symbol of O and atomic number of 8. Oxygen is the gas
that we inhale and goes to our respiratory system. According to the latest
research, it is one of the most abundant gas in earth, it is on the third
place. Most organic molecule contains oxygen like proteins, carbohydrates, fats
and nucleic acid. Trees also produce oxygen and intake the carbon dioxide.
