The amount of energy extracted from a glucose molecule during respiration without oxygen is

Explanation

During anaerobic respiration, such as in fermentation processes, only about 2% of the energy stored in a glucose molecule is extracted. This is because anaerobic pathways do not fully oxidize glucose and thus capture less energy compared to aerobic respiration, which yields about 38% of energy. The incorrect options (4%, 6%, and 8%) overestimate the energy yield of anaerobic respiration.