natural selection selective breeding asexual reproduction behavioral adaptation
I gave my students this multiple choice question: In a lab, a bacterial strain shows resistance to an antibiotic. The presence of the antibiotic allows an existing variant within the genetic code to help the bacteria survive. The resistance of bacteria due to an existing genetic variant can be best described as which process?

Only one answer is correct among these 4 choices:
- natural selection
- selective breeding
- asexual reproduction
- behavioral adaptation

Could you tell me which one is correct?

natural selection