Just the facts:

Oxygen Definition & Meaning - Merriam-Webster

The origin of his word was two Greek elements, oxys, meaning "sharp, sour," and -genēs, meaning "born, generated."  For this reason, Lavoisier named it (in French) principe oxygène, or literally meaning "acid producer, because at first it was held to be the essential component in the formation of acids.  The word oxygen came into use in English in the late 18th century. 

Earth's oxygen supply originated with cyanobacteria, tiny water-dwelling organisms that survive by photosynthesis. In that process, the bacteria convert carbon dioxide and water into organic carbon and free oxygen.  

Chemical equations are constructed in such a way that they show all of the molecules involved. Because each oxygen molecule has two oxygen atoms, it is written with a \[2\]  or O2 (with the 2 being a subscript). We breathe diatomic oxygen molecules, which are made up of only two oxygen atoms.

Oxygen is not flammable onto itself.

Oxygen is an oxidizer that makes flames stronger, brighter, and more explosive. 

Oxygen can lower the ignition temperature of other materials, causing them to catch fire.

Oxygen is so reactive, chemists have given the process a special name: oxidation.

Earth is a terrible place for a laboratory to understand the universe. The majority of the universe exists as a vacuum without gravity nor does it possess an oxidizing atmosphere.

We humans are only now beginning to grasp how ignorant we actually are.