G
o
o
g
l
e
×
Please click
here
if you are not redirected within a few seconds.
All
Images
Books
Videos
Maps
News
Shopping
Search tools
Any time
Any time
Past hour
Past 24 hours
Past week
Past month
Past year
All results
All results
Verbatim
Oxygen cycle
View all
Oxygen cycle refers to the movement of oxygen through the atmosphere, biosphere and the lithosphere. The oxygen cycle demonstrates how free oxygen is made available in each of these regions, as well as how it is used.
Wikipedia