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A-LevelBiologyTransport in mammalsMay/June 2020Paper 1 Q311 Mark

What correctly describes the significance of the increase of the red blood cell count of humans who move from living at low altitude to high altitude?

AAfter a few weeks at high altitude, the number of red blood cells increases to compensate for the lower availability of oxygen in the air.
BAt high altitude, the bone marrow produces more red blood cells to provide binding sites for the increased number of oxygen molecules available.
CAt high concentrations of oxygen in the blood, a cytokine stimulates the production of red blood cells to increase the oxygen-carrying capacity of the blood.
DAfter only a few days at high altitude the number of red blood cells increases considerably to compensate for the lower availability of oxygen in the air.

✓ Correct Answer

The correct answer is A: After a few weeks at high altitude, the number of red blood cells increases to compensate for the lower availability of oxygen in the air.

📋 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 May/June 2020 examination, Paper 1 Variant 2.

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