`O, O_2, O_3`
Various forms of oxygen are given above.
a) Which among these forms is not found in nature?
b) Which is the component that is known as a life supporter and contributes 21% of the atmosphere?
c) Which form is seen as a separate layer in the topmost portion of the atmosphere called as stratosphere?

Explanation

a)O
b) .O_2.
c) .O_3. ozone layer