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Transport in animals

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Question 20

Changes to the heart and circulatory system begin in the first few weeks of pregnancy. The graphs in the figure show the changes in stroke volume and heart rate that occur during pregnancy.

Two line graphs showing cardiovascular changes during pregnancy from week 0 to week 40. Top graph: Stroke Volume (cm³) vs Length of pregnancy (weeks). Grid lines: y-axis from 60 to 90 with intervals of 5, each small square represents 0.5 cm³; x-axis from 0 to 40 with intervals of 4. The data points are: Week 0: 65, Week 4: 67, Week 8: 75, Week 12: 79.5, Week 16: 83, Week 20: 85, Week 24: 85, Week 28: 83, Week 32: 82, Week 36: 81, Week 40: 83. Bottom graph: Heart Rate (bpm) vs Length of pregnancy (weeks). Grid lines: y-axis from 72 to 90 with intervals of 2, each small square represents 0.2 bpm; x-axis from 0 to 40 with intervals of 4. The data points are: Week 0: 75, Week 4: 79, Week 8: 80, Week 12: 82.5, Week 16: 82.5, Week 20: 82.5, Week 24: 83.5, Week 28: 84.5, Week 32: 87.6, Week 36: 87.6, Week 40: 86.

a.

Use the data in the figure to calculate the cardiac output in week 8. Include appropriate units.

[3]
b.

Suggest an advantage of the increase in cardiac output.

[2]

Transport in animals Questions

  1. A Level
  2. /Biology
  3. /Transport in animals