A-LevelBiologyBiodiversity and conservationOct/Nov 2012Paper 1 Q401 Mark
The total rate at which producers synthesise organic material is called gross primary productivity (GPP). The rate at which producers store organic material as new tissue is called net primary productivity (NPP). What shows the relationship between GPP and NPP?
ANPP = GPP × respiration
BNPP = GPP ÷ respiration
CNPP = GPP + respiration
DNPP = GPP – respiration
✓ Correct Answer
The correct answer is D: NPP = GPP – respiration
📋 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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