(4)

Less than seven percent of the energy in glucose is released from lactic acid fermentation and moreover not all of it is stored as ATP.

(4)

Anaerobic respiration or fermentation can be of two types, i.e., lactate fermentation and ethanol fermentation. Lactate fermentation produces lactic acid only as pyruvic acid produced in glycolysis is directly reduced by NADH to form lactic acid and no ${\mathrm{CO}}_2$ is produced. Alcoholic (ethanol) fermentation involves conversion of pyruvate to acetaldehyde, hence, ${\mathrm{CO}}_2$ is released.