Oxygen

Oxygen is a colorless, odorless gas that is essential for all known forms of life. It constitutes about 20 percent of the air we breathe on Earth. Not only does oxygen sustain life, it plays a vital role in many natural processes, including photosynthesis. In addition, oxygen is used in many industrial processes, such as the production of steel, and it is also a component of fuel used in rocket engines. Oxygen is critical to human health, as it helps to supply our cells with the energy they need to function properly. Without oxygen, life would not be possible.