A-LevelBiologyGas exchangeFeb/Mar 2017Paper 1 Q351 Mark
The graph shows the oxygen dissociation curves of haemoglobin from two species of mammal, S and T. Which statements could explain the difference in the oxygen dissociation curves of species S and species T? 1 Species T has a lower haemoglobin concentration in its red blood cells than species S. 2 The haemoglobin in species T has a lower affinity for oxygen than the haemoglobin in species S. 3 Species T lives at higher altitudes than species S.
A1, 2 and 3
B1 and 2 only
C2 only
D3 only
✓ Correct Answer
The correct answer is C: 2 only
📋 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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