A-LevelBiologyTransport in mammalsFeb/Mar 2023Paper 1 Q201 Mark

The estimated total number of red blood cells in the human body is 2.5 × 10¹³. It is estimated that, each day, 2.5 × 10¹¹ red blood cells are removed from the circulation and are replaced by stem cells in the bone marrow. Which percentage of the total number of red blood cells is replaced each day?

Q: What topic does this question test?

This question tests Transport in mammals in A-Level Biology (syllabus code 9700). It is worth 1 mark.

A0.01%

B0.1%

C1%

D10%

✓ Correct Answer

The correct answer is C: 1%

📋 Examiner Report & Trap Analysis

Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...

🎯 Mark Scheme Breakdown

Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.

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About This A-Level Biology Question

Topic

This multiple-choice question tests Transport in mammals in A-Level Biology (syllabus code 9700). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Biology Feb/Mar 2023 examination, Paper 1 Variant 2.

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