Oxygen or O2 is a chemical found in the universe. Humans need Oxygen to survive. Oxygen is in our atmosphere and the air that we breathe!! Oxygen helps the animals on this planet survive. Oxygen is a building block of so many elements like Water, or even Carbon Monoxide. Oxygen can be useful for things like rocket fuel. Oxygen in our bodies keeps our organs running and functioning properly. Oxygen comes from many places. There are types of algae and bacteria in the ocean that produce large quantities of Oxygen gas. Millions of years ago, lots of these bacteria helped create the Earth’s Oxygen atmosphere. Also, plants make Oxygen too! Plants take in Carbon dioxide, water, and sunlight and make sugar and Oxygen gas. That is called photosynthesis. Plants release that Oxygen gas into the atmosphere! This is how the Oxygen that we breathe comes from!