Which statement most accurately defines antibiotic resistance and explains the role of antibiotic use in its emergence?

A clinician treats a mixed bacterial infection with an antibiotic and afterwards the remaining population is resistant. Which explanation best describes what occurred?

Consider a bacterial population where a resistance gene is initially present in 0.1% of cells but on a conjugative plasmid with high transfer rate. After several days in an antibiotic-rich environment, which pattern of spread would you expect compared with a scenario where the same resistance gene is a chromosomal mutation present in 0.1%? Choose the best analysis.

Which mechanism is best illustrated by production of beta-lactamase enzymes by bacteria?

Using reported data of 256,000,000 antibiotic prescriptions in a population of 350,000,000 people over one year, what is the average number of antibiotic prescriptions per person per year (per-capita exposure)? Show your calculation.