What is fermentation and what role does it play in anaerobic respiration?

• A. Fermentation is the process of breaking down proteins to produce ATP in the absence of oxygen, serving as a major step in anaerobic respiration.
• B. Fermentation is the process of breaking down lipids to produce ATP in the absence of oxygen, serving as a major step in anaerobic respiration.
• C. Fermentation is the process of breaking down sugar to produce ATP in the presence of oxygen, serving as a major step in aerobic respiration.
• D. Fermentation is the process of breaking down sugar to produce ATP in the absence of oxygen, serving as a major step in anaerobic respiration.

Answer: (D)