Why does anaerobic respiration produce less energy than aerobic respiration ?
Anaerobic respiration produces less energy as compared to aerobic respiration due to the following reasons :

1. Incomplete break down. There is incomplete breakdown of repiratory substrate.

2. Incomplete oxidation. At least one of the products of anaerobic respiration is organic. It can be further oxidised to release energy.

3. Re-utilization. NADH2 produced during glycolysis is often re-utilized.

4. No A TP formation. ATP formation does not, occur during regeneration of NAD+.

5. Absence of ETC. Electron transport chain is absent.

6. No use of oxygen. Oxygen is not used for receiving electrons and protons.