Aerobic respiration is more efficient because:

i) Aerobic respiration produces more energy as compared to anaerobic respiration. It is a high energy yielding process.

ii) Anaerobic respiration produces less energy as compared to anaerobic respiration.

Efficiency is attributed to the number of ATP produced from one molecule of glucose. In Aerobic respiration produces 38 ATP molecules from a single glucose molecule while Anaerobic respiration produces only 2 ATP molecules from a single glucose molecule. Therefore, aerobic respiration is more efficient than anaerobic respiration.