Plants are the main source of breathable
oxygen for all animals that depend on it.
 During photosynthesis plants absorb
carbon dioxide and release oxygen.

99.5% of all oxygen is located in the crust
and mantle of the earth.
 .36% of the earth’s oxygen is in the
atmosphere which is the oxygen we
breathe.
 Although oxygen is the most abundant
element on the planet we can only use
a small portion of it.

The chemical formula in photosynthesis is
6CO2 + 6H2O + energy → C6H12O6 + 6O2.
 The chemical formula in chemical
weathering for oxidized iron rocks is 4FeO
+ O2 → 2Fe2O3.
 These are the most important chemical
formulas having to do with oxygen.

Humans along with every other animal completely
depend on oxygen to make possible chemical
reactions in their body's.
 The worst thing humans can do is to destroy forests
which they are doing.
 Without any plants or forests the oxygen cycle will
cease to occur killing all humans.
