Question

darwin hypothesized that there are definite steps to natural selection. consider the model of bacterial resistance to antibiotics. how would darwin explain step 1? a bacteria adapt to environmental changes. b in any population, genetic variation exists. c in any population, some individuals are weaker than others. d some bacteria alter their dna in a response to environmental changes. e sexual reproduction results in genetic variation.

Explanation:

Darwin's natural selection starts with genetic variation in a population. For bacterial antibiotic resistance, Step 1 would involve pre-existing genetic variation (some bacteria have resistance genes before antibiotic exposure). Option B states "In any population, genetic variation exists," which aligns with this foundational step. Other options are incorrect: A and D imply adaptation/DNA change in response to environment (Lamarckian, not Darwinian); C is vague about variation; E is irrelevant as bacteria reproduce asexually.

Answer:

B. In any population, genetic variation exists.