Answer
Production of energy without oxygen.
Explanation :
In anaerobic respiration, the oxygen is not used as electron acceptor other compound having less potential to accept electron are used so less energy is produced. Glucose is partially broken and lactate is formed as a by-product of this reaction. Anaerobic respiration is mostly carried in the lower organism and some time in a higher organism like a human when oxygen is Less and there is a need for more energy.