Which of the following statements is incorrect?

During aerobic respiration, role of oxygen is limited to the terminal stage.

In ETC (Electron Transport Chain), one molecule of $\displaystyle \mathrm{NADH}+\mathrm{H}^{+}$gives rise to $\displaystyle 2$ ATP molecules, and one $\displaystyle \mathrm{FADH}_2$ gives rise to $\displaystyle 3$ ATP molecules.

ATP is synthesized through complex V.

Oxidation-reduction reactions produce proton gradient in respiration.