Lactic Acid Breakdown Location Steps:

• Recall that lactic acid forms during anaerobic respiration in muscles.
• Note that it is transported to the liver for conversion back to glucose via the Cori cycle.
• Identify diagram labels: A (muscle), B (blood), C (mitochondria), D (liver).
• Match D to the liver as the site of breakdown.

Why D is correct:

• Lactic acid is oxidized to pyruvate in the liver, per the Cori cycle, regenerating glucose for energy.

Why the others are wrong:

• A: Muscles produce lactic acid but do not break it down.
• B: Blood transports lactic acid, not the breakdown site.
• C: Mitochondria handle aerobic respiration but not lactic acid conversion.

Not enough information: Diagram labels are ambiguous without the figure.

Final answer: D