What is the fundamental difference between fermentation and anaerobic cellular respiration?

1. When aerobic respiration cannot run, NADH must still be reoxidized for glycolysis to continue. 2. Some living systems use an organic molecule as the final electron acceptor, and those processes are called fermentation. 3. Others use an inorganic molecule as the final acceptor instead. 4. Both routes count as anaerobic cellular respiration, in which organisms convert energy in the absence of oxygen. 5. So the dividing line is organic against inorganic, not oxygen against no oxygen. 6. An answer saying fermentation needs oxygen contradicts the whole premise of a no-oxygen pathway. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 7 "Cellular Respiration", section 7.5 Metabolism without Oxygen_