Oxygen is critical for aerobic respiration. Explain its role with respect to $ETS$.

(N/A) The importance of $O_{2}$ in aerobic respiration is as follows:
$1$. Aerobic respiration begins with the glycolysis of glucose in the cytoplasm.
$2$. This is followed by the Krebs cycle,and finally,the Electron Transport System $(ETS)$ occurs in the inner mitochondrial membrane.
$3$. $O_{2}$ acts as the final electron acceptor in the $ETS$.
$4$. It accepts electrons and protons to form water $(H_{2}O)$.
$5$. If $O_{2}$ is absent,electrons cannot pass through the electron transport chain,preventing the formation of a proton gradient across the inner mitochondrial membrane.
$6$. Consequently,the proton pump stops,and $ATP$ synthesis via oxidative phosphorylation cannot occur. Thus,$O_{2}$ is essential for the completion of aerobic respiration.