Multiple choice

During heavy exercise, the buildup of lactic acid in muscle cells results in

  1. the Calvin cycle

  2. the Krebs cycle

  3. fermentation

  4. oxygen debt

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When lactic acid builds up in muscle cells during intense exercise, it creates an oxygen debt that must be repaid. This is why you continue to breathe heavily for a period after stopping strenuous physical activity.