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A-LevelBiologySelection and evolutionFeb/Mar 2018Paper 1 Q371 Mark

Bacteria that infect skin wounds can become resistant to the antibiotic commonly used to kill them. Which statement explains how these bacteria could become resistant to the antibiotic?

AExposure to the antibiotic causes a change in the bacterial cell wall, preventing the antibiotic from working.
BOther bacteria that normally protect the skin against infection are killed by the antibiotic, allowing the infectious bacteria to survive.
CRandom mutations in DNA allow some of the bacteria to survive in the presence of the antibiotic.
DThe antibiotic causes the bacterial DNA to mutate, allowing the bacteria to survive in the presence of the antibiotic.

✓ Correct Answer

The correct answer is C: Random mutations in DNA allow some of the bacteria to survive in the presence of the antibiotic.

📋 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 Selection and evolution in A-Level Biology (syllabus code 9700). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Biology Feb/Mar 2018 examination, Paper 1 Variant 2.

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