0 a chemical element that is a gas with no smell or colour. Oxygen forms a large part of the air on earth, and is needed by animals and plants to live. -- 氧，氧气
Mountain climbers use oxygen when they reach higher altitudes.
Plants are the main source of atmospheric oxygen.
The symbol for oxygen is O2.
Numerous substances are found in nature and in the body that function as protective agents against oxygen-free radicals.
In each case, inversion of configuration was demonstrated using thio-substituted non-bridging phosphate oxygens.
This effect allows oxygen to be released from the molecule at venous oxygen pressure.
