Bacteria with a mutation that makes them resistant to an antibiotic survive treatment. Which statement explains why the proportion of resistant bacteria increases?
Answer and explanation
Correct answer: C. Resistant bacteria survive and reproduce, but sensitive ones die
- Step 1: The antibiotic kills sensitive cells.
- Step 2: Survivors multiply and pass on the allele: natural selection.
Answer
Resistant bacteria survive and reproduce, but sensitive ones die.
Why not the others: The antibiotic causes the mutation in each bacterium: mutations occur at random before treatment. The antibiotic makes each sensitive bacterium resistant over time: sensitive bacteria do not become resistant individually. The resistant bacteria are larger than the sensitive ones: size is not involved.
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