Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Cells of different tissues essentially require CO\(_2\) to generate energy and perform metabolic functions.
Reason (R) : Deficiency of oxygen or hypoxia results in failure to carry metabolic functions.
In the light of the above statements, choose the most appropriate answer from the options given below :