Anaerobic respiration in muscles yields lactic acid

Steps:

• Recall that anaerobic respiration occurs without oxygen, using glucose as fuel.
• In muscle cells, glucose breaks down via glycolysis to pyruvate.
• Pyruvate converts to lactic acid to regenerate NAD+ for continued energy production.
• The net products are lactic acid and ATP, without carbon dioxide.

Why D is correct:

• The biochemical equation for muscle anaerobic respiration is C6H12O6 → 2 lactic acid + 2 ATP, confirming lactic acid as the primary byproduct.

Why the others are wrong:

• A: Describes yeast fermentation, not muscle processes.
• B: Omits lactic acid, the key end product.
• C: Includes carbon dioxide, which is not released in muscle anaerobic respiration.

Final answer: D