Final answer:
c) Antibiotic-resistant bacteria survive and reproduce, passing on resistance genes. Natural selection results in antibiotic-resistant bacteria through the survival and reproduction of bacteria with resistance genes.
Step-by-step explanation:
The best description of how natural selection results in bacteria that are antibiotic-resistant is option c) Antibiotic-resistant bacteria survive and reproduce, passing on resistance genes.
When antibiotics are used to treat bacterial infections, the antibiotics kill most of the bacteria. However, some bacteria may already possess genetic mutations that make them resistant to the antibiotic. These resistant bacteria survive and reproduce, passing on the resistance genes to their offspring. Over time, the population of bacteria becomes dominated by antibiotic-resistant strains.
It is important to note that the resistance genes were already present in the bacterial population and were not caused by the antibiotic itself. The antibiotic simply selected for the individuals with resistance genes, leading to the proliferation of antibiotic-resistant bacteria.