Answer:
oxygen is not present is correct option.
Step-by-step explanation:
- Anaerobic respiration occurs in the absence of Oxygen, it uses organic or inorganic molecules as electron acceptors.
- In anaerobic respiration, there is a breakdown glucose molecule in the absence of oxygen. In this process, lactic acid is produced
- During the intense exercise supply of oxygen is less when oxygen is less, in that case, muscle cell performs anaerobic respiration and then pyruvate is converted into lactic acid.