Changes

Oxygen is highly reactive, and in many other elements and compounds undergo [[exothermic reaction]]s with it (they [[combustion|burn]] or [[oxidization|rust]]).  If it were not for its continual replenishment as a waste product of plant [[photosynthesis]], the atmospheric oxygen would disappear, forming compounds with other chemicals at the earth's surface.

Oxygen is highly reactive, and in many other elements and compounds undergo [[exothermic reaction]]s with it (they [[combustion|burn]] or [[oxidization|rust]]).  If it were not for its continual replenishment as a waste product of plant [[photosynthesis]], the atmospheric oxygen would disappear, forming compounds with other chemicals at the earth's surface.

Many [[animal]]s depend upon oxygen as a highly efficient ingredient for breaking down [[food]] for [[energy]], due to its reactivity.  Those that do not are called "[[anaerobic]]", meaning "without air", and include many important [[bacteria]].

Many [[animal]]s depend upon oxygen as a highly efficient ingredient for breaking down [[food]] for [[energy]], due to its reactivity.  Those that do not are called "[[anaerobic]]", meaning "without air", and include many important [[bacteria]]. It is a notoriously dangerous poison, especially when used in conjunction with godless killing machines.

==References==

==References==