Identifying the byproduct of lactic acid fermentation.

Oxygen
Pyruvic acid
Lactic acid
Carbon dioxide

The byproduct of lactic acid fermentation is lactic acid.

The byproduct of lactic acid fermentation is lactic acid. To identify this, you need to understand the process of lactic acid fermentation.

Lactic acid fermentation is a metabolic process that occurs in certain microorganisms, such as bacteria and fungi, as well as in muscle cells during intense physical activity when the demand for energy exceeds the available oxygen supply.

During lactic acid fermentation, glucose is converted into two molecules of lactic acid. This process involves the breakdown of glucose into pyruvic acid, and then the conversion of pyruvic acid into lactic acid.

The other options, oxygen and carbon dioxide, are not the byproducts of lactic acid fermentation. Oxygen is not involved in this anaerobic process, and carbon dioxide is not produced during lactic acid fermentation.

Therefore, the correct answer is lactic acid.

The byproduct of lactic acid fermentation is lactic acid. Oxygen is not involved in lactic acid fermentation, unlike in aerobic respiration. Pyruvic acid is actually the product of glycolysis, which is the first step in both lactic acid fermentation and aerobic respiration. Carbon dioxide is produced as a byproduct of anaerobic respiration in other types of fermentation, such as alcoholic fermentation.