Why do anaerobic cellular systems use fermentation? what would happen if they didn't?

Anaerobic systems use fermentation because they don't need oxygen to obtain energy( ATP). Anaerobic means exactly that: no oxygen. In fermentation the glucose is consumed by yeast/bacteria and originates organic acids, gases, or alcohol. If they didn't have this process they wouldn't survive because there would be no energy for the cells.

Idk little ngr try paying attention in school and you would know ngr

It's important for a woman to know she is pregnant within the first trimester so she won't consume any alcohol or cigarettes which will harm the baby.