Continuing Evolution Practice Test

The antibiotic caused specific mutations to arise in the bacterial DNA that conferred resistance, allowing the population to adapt directly to the presence of the drug.

The initial antibiotic treatment acted as a selective pressure, allowing a few naturally resistant bacteria to survive and reproduce, leading to a population that is now largely resistant.

The patient's immune system was weakened by the initial infection and antibiotic use, preventing it from effectively combating the bacterial population during the second treatment.

The bacteria that survived the first treatment developed an immunity to the antibiotic and passed this acquired trait on to their offspring, making the new population immune.