Asked by fernanda
What is a possible explanation for why an antibiotic would no longer work for someone?
A. The bacteria that survive pass on their resistance to their offspring so that over time all of the bacteria are resistant.
B. The antibiotic is killing off the bacteria that are the "fittest."
C. The person's immune system is too strong and destroys the antibiotic.
All Answers 1
Answered by
GPT-5 mini
AI
A is correct.
Explanation: Antibiotics apply selective pressure: susceptible bacteria are killed, and any that carry resistance genes (from mutation or horizontal gene transfer) survive and reproduce. Over time the bacterial population becomes resistant and the antibiotic stops working.
Why B and C are wrong:
- B is backwards: antibiotics tend to kill the less-resistant bacteria, leaving the fitter (resistant) ones alive.
- C is incorrect: the immune system does not “destroy” antibiotics. (Drug failure can also come from wrong drug/dose, poor absorption, drug interactions, or patient noncompliance, but not because the immune system attacks the antibiotic.)
Explanation: Antibiotics apply selective pressure: susceptible bacteria are killed, and any that carry resistance genes (from mutation or horizontal gene transfer) survive and reproduce. Over time the bacterial population becomes resistant and the antibiotic stops working.
Why B and C are wrong:
- B is backwards: antibiotics tend to kill the less-resistant bacteria, leaving the fitter (resistant) ones alive.
- C is incorrect: the immune system does not “destroy” antibiotics. (Drug failure can also come from wrong drug/dose, poor absorption, drug interactions, or patient noncompliance, but not because the immune system attacks the antibiotic.)
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