Evolution · NEET Preparation Zoology
A bacterial population contains a few antibiotic-resistant individuals before exposure to an antibiotic. After exposure, most susceptible bacteria di…
Practice question from Evolution (NEET Preparation Zoology), with the correct answer and a step-by-step solution.
easy · MCQ · Q-B7260B
A bacterial population contains a few antibiotic-resistant individuals before exposure to an antibiotic. After exposure, most susceptible bacteria die and resistant bacteria reproduce. Which statement best explains this event?
- A.The antibiotic directly creates the required resistance in every surviving bacterium.
- B.The antibiotic selects pre-existing resistant variants, increasing their frequency in the population.Correct answer
- C.Individual bacteria develop resistance because they intentionally adapt to the antibiotic.
- D.The antibiotic changes the bacteria into a completely different species in one generation.
Solution
Variation, including antibiotic resistance, may already exist in a population. Natural selection increases the frequency of resistant variants when the antibiotic eliminates susceptible bacteria.
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