Cambridge IGCSE Biology practice
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At a glance
MCQ
Type
cambridge_mcq
Style
Topic
Heart
Exam-style question
Which of the following is a control variable in a heart rate and exercise experiment?.
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Flashcard 1 of 6
Question 1 of 5
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Method
1. Measure your resting heart rate by counting your pulse for 30 seconds and multiply by 2 to get beats per minute. 2. Perform moderate physical activity (e.g., jogging on the spot) for 3 minutes. 3. Immediately after exercise, measure your heart rate again using the same method. 4. Record your results. 5. Repeat the activity and measurements two more times and calculate the average heart rate after exercise.
| Step | Action |
|---|---|
| 1 | Measure resting heart rate |
| 2 | Perform moderate exercise for 3 minutes |
| 3 | Measure heart rate immediately after exercise |
| 4 | Record results |
| 5 | Repeat twice and calculate average |
Identify the independent variable in this investigation.
Aim for approximately 1 distinct marking point.
Identify the dependent variable in this investigation.
Aim for approximately 1 distinct marking point.
Describe one control variable that should be kept constant in this investigation.
Aim for approximately 1 distinct marking point.
Explain why heart rate increases during physical activity.
Aim for approximately 2 distinct marking points.