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8 marksThe Circulatory System of Mammals

CAPE Biology Unit 2 · May/June 2022 · Paper 2 · Question 2(d)

Athletes are advised that peak performance can be obtained with a heart rate between 80-120 beats per minute (bpm). When heart rate is above 160 bpm, the heart cannot fill efficiently and cardiac output decreases. Cardiac output is defined as stroke volume × heart rate.

Justify why cardiac output increases during peak performance in athletes (80–120 bpm) but decreases when heart rate exceeds 160 bpm.

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Other parts of this question

  1. 2(a)(i)On Figure 1, insert labels to identify THREE different types of root cells.[3 marks]
  2. 2(a)(ii)Insert arrows on Figure 1 to illustrate the direction of water movement from the soil into the different areas of the plant root shown in the diagram.[3 marks]
  3. 2(a)(iii)Describe how water potential facilitates the movement of water from the soil into the plant roots.[2 marks]
  4. 2(b)(i)Compare the observed differences in transpiration rates at 60 days and 75 days at the highest intensities and lowest intensities.[4 marks]
  5. 2(b)(ii)Explain the differences between the transpiration rates on a sunny day and at night-time.[3 marks]
  6. 2(c)In the space provided below, draw a diagram of ONE red blood cell and ONE white blood cell shown in Figure 3.[7 marks]

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