This question asks. Fermentation permits the continued extraction of energy from glucose in the absence of oxygen. If glucose metabolism is anaerobic, why's fermentation necessary for glad causes to continue? So during, like Collis, we're going to see that n a d plus is going to be reduced to an a D. H. And that means that is going to gain electrons. And we will also gain this hydrogen becoming any D. H. And it was any d plus before. Now it's any th okay. The problem here is that we need this n a d plus to be reduced for glad costs to occur. So this any d plus must be at the start of black Collis in water for like, some for in order to forget costs to proceed. Now what we did, we would have during a name a aerobic respiratory reaction where there would be auction present. We would have the electrons of the electron transport chain and the Krebs cycle basically regenerate this any d plus right there'll be toe oxidize the any D h generate any plus via the electron transport chain. So when auction is, their oxygen will actually oxidize the an idiot so we could actually right if oxygen present, then on a th is oxidized, meaning it gets converted back into any Plus. Now, if oxygen is not present than what we have to do, well, we have to still oxidize. And a d h of the requirement for any D plus is not just going to vanish. So we need to find a different way. So the different way would be to go through fermentation, which will also oxidize and in the age to form an 80 plus. So that is why fermentation is going to be necessary for black office to continue because it will regenerate the any D plus right here that is going to be necessary for, like, policies to occur.