What is the final product of fermentation when pyruvic acid undergoes this process?

The final product of fermentation when pyruvic acid is involved can indeed be either alcohol or lactic acid, depending on the type of fermentation occurring. In alcoholic fermentation, which is commonly seen in yeast, pyruvic acid is converted into ethanol (alcohol) and carbon dioxide. This process allows yeast to regenerate NAD+, which is essential for glycolysis to continue producing ATP in anaerobic conditions.

On the other hand, in lactic acid fermentation, which commonly occurs in muscle cells during intense exercise or in some bacteria, pyruvic acid is directly converted into lactic acid. This process also serves to regenerate NAD+, enabling glycolysis to persist and generate energy even when oxygen levels are low.

Thus, the correct answer reflects the two significant forms of fermentation where pyruvic acid serves as the starting point, leading to the production of either alcohol or lactic acid. This versatility in fermentation pathways highlights the adaptability of organisms in energy production under anaerobic conditions.