Oxygen is always needed to survive for all living beings and it is about 21% of all the elements of atmosphere.

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A Chemist from Sweden “Carl Scheele” in 1772 discovered Oxygen for the first time and later in 1774 Joseph Priestly, a Chemist from England published his discovery about Oxygen and in 1775, Antoine Lavoiser, a Chemist from France too, discovered oxygen and named it as “Oxygen”. Oxygen is a Greek word that means “acid former”.

There is a lot of dispute about who actually discovered Oxygen and credit of the discovery was given to different people mentioned above.

At present there has been a lost of decrease in number of trees and forest areas covering earth surface and as trees are very helpful in conversion of carbon to oxygen at night days are not so far when oxygen may be scarce too.