What is the main product of anaerobic respiration in animals?

• A. Carbon dioxide
• B. Lactic acid
• C. Alcohol
• D. Glucose

Answer: (B)

The main product of anaerobic respiration in animals is lactic acid. This process occurs when oxygen is in short supply during strenuous exercise or in situations where cells are metabolizing energy quickly. In the absence of oxygen, the cells convert glucose into energy through glycolysis, which results in the production of pyruvate. Instead of further processing pyruvate in the presence of oxygen, the pyruvate is converted into lactic acid. This buildup of lactic acid is what can lead to muscle fatigue and discomfort during intense physical activity.

In contrast, carbon dioxide is a byproduct of aerobic respiration, while alcohol is typically produced in anaerobic respiration by yeast and some bacteria, not by animal cells. Glucose is the starting material for both aerobic and anaerobic respiration processes but is not a product. Thus, lactic acid is the most accurate answer for the end product of anaerobic respiration specifically in animal cells.