Explain the history of respiration.

(N/A) During the process of respiration,$O_2$ is utilized and $CO_2$,$H_2O$,and energy are released as products. The combustion reaction requires $O_2$.
However,some cells live in environments where $O_2$ may or may not be available.
The first cells on this planet lived in an atmosphere that lacked $O_2$.
Even among present-day living organisms,several are adapted to anaerobic conditions.
Some of these organisms are facultative anaerobes,while in others,the requirement for anaerobic conditions is obligate.
In any case,all living organisms retain the enzymatic machinery to partially oxidize glucose without the help of $O_2$. This breakdown of glucose into pyruvic acid is called glycolysis.