BI-1130
The heart
Biology · Secondary 3 · Medium · The heart
During a 400 m sprint, a student’s pulse rate increases from 70 beats per minute at rest to 150 beats per minute during exercise. Which is the best explanation for this increase?
- More oxygen and glucose must be delivered to muscles and more carbon dioxide removed.
- The heart muscles become weaker and need to beat faster.
- The blood becomes thicker and is harder to pump.
- The lungs stop working so the heart must work harder.
Sign in to check your answer and see the hint and the worked explanation. Free on PrepLab High.