Question

natural selection
changes in gene frequency
which of the following mechanisms of change in gene frequencies is responsible for the antibiotic resistance of e coli in this experiment?
multiple choice
genetic drift
natural selection
population bottleneck
founder effect

Explanation:

Antibiotic - resistant E. coli survive and reproduce in the presence of antibiotics. Natural selection favors these resistant strains as they have a higher fitness in the antibiotic - containing environment. Genetic drift is due to random changes, population bottleneck is a reduction in population size, and founder effect is related to the establishment of a new population from a small group. None of these other factors directly explain antibiotic resistance in this context.

Answer:

B. natural selection