CAIE IGCSE Biology 12.3.7 How the Oxygen Debt Is Removed After Questions

Explain how a fast heart rate transports lactic acid to the liver and how deeper, faster breathing supplies oxygen for its aerobic breakdown.

Syllabus
2026–2028
Course
Biology 0610

Exam points

  • Use oxygen-consumption or blood-lactate recovery data to identify when an oxygen debt is being removed.
  • Explain how a continued fast heart rate transports lactic acid in blood from the muscles to the liver.
  • Explain how continued faster, deeper breathing supplies oxygen for aerobic respiration of lactic acid.
  • State that the liver removes lactic acid by aerobic respiration.

CAIE IGCSE Biology 12.3.7 How the Oxygen Debt Is Removed After Questions question 1

[Maximum number: 7]

An athlete monitored their heart rate and breathing rate before, during and after vigorous exercise.

Fig. 6.1 shows the results.

Fig. 6.1

Fig. 6.1

Complete the sentences to describe and explain the results shown in Fig. 6.1.
After exercise, it takes minutes for the athlete's breathing rate to return to its resting rate.

The heart rate decreases by beats per minute between 20 and 40 minutes.

The heart rate and breathing rate do not immediately return to their resting rates because anaerobic respiration has occurred.

Lactic acid has built up in causing an oxygen .

The heart rate remains high to transport lactic acid to the .

The breathing rate remains high to supply for the respiration of lactic acid.

All question bank results loaded