After 1 year of widely prescribed use, reports surface that bacterial infections disappear for up to 2 weeks after taking the prescribed antibiotic but then reappear, sometimes worse than the first time. Which of the following explanations might the FDA use to defend their choice of antibiotic to treat the infection? a) Patients' bodies are evolving over the year to create environments that are friendly to the growth of the bacteria. b) Patients are not taking the antibiotic for the length of time prescribed and so selection for resistant bacteria that can survive a limited course of antibiotic is occurring. c) Sexual dimorphism allowed for larger bacteria cells to outcompete smaller ones, therefore enabling larger bacteria cells to continue to multiply. d) Stabilizing selection over the year has allowed for the bacteria to remain at a high level in patients bodies.

b

Explanation:

The correct answer would be that patients are not taking the antibiotic for the length of time prescribed and so selection for resistant bacteria that can survive a limited course of antibiotic is occurring.

When the concentration of the antibiotic in the blood is not up to the minimum bactericidal concentration as a result of inadequate dosage, natural selection acts on the bacterial population and those with the antibiotic-resistant gene are selected over those without the resistant gene.

Consequently, the surviving bacteria with the resistant gene regroup, multiply and become dominant in the population than ever before. Subsequent use of the same antibiotic by patients will be met with the antibiotic-resistant gene and renders the antibiotic ineffective in the treatment of the disease caused by the bacterial pathogen.

The correct option is b.

1. a tropical dry forest carries out more rapid nutrient cycling