Which statement best explains why fermentation occurs in mammals? It enables mammals to generate additional ATPATP in an oxygen‑rich environment. It breaks down lactic acid to generate a small amount of ATPATP under anaerobic conditions. It generates ethanol, which can be used as an alternative source of energy. It produces an acid that maintains blood pH within a narrow range. It allows glycolysis to continue under anaerobic conditions by replenishing NAD+NAD+ .

The last option.

Explanation:

Fermentation/ Anaerobic respiration is important to supply ATP in the absence of oxygen.

In the presence of oxygen, glycolysis, Kreb's cycle and oxidative phosphorylation happen to provide about 32 ATP molecules. In its absence, only glycolysis can take place because it's the only step that doesnt need oxygen, to give a net supply of 2 ATP.

Even though glycolysis doesn't need oxygen, it needs NAD, and if the reduced NAD doesn't lose its hydrogens via oxidative phosphorylation, pyruvate (the end product of glycolysis) becomes the recipient of the hydrogen.

Pyruvate gets reduced to lactate.

your answer is "the 1950's"