A. produce amino acids for protein synthesis

B. generate a proton gradient for ATP synthesis

C. oxidize glucose to generate reduce electron carriers

D. generate alcohol for beverages

E. regenerate NAD⁺ from NADH allowing glycolysis to continue

Fermentation allows continued glycolysis by regenerating NAD⁺ from NADH. NAD⁺ is limiting, and must be reformed to allow the continuation of the glycolytic degradation of glucose producing ATP.