Which of the following best describes why antibiotics with a mode of action like azithromycin are selectively toxic? a. Because humans obtain folic acid through their diet. b. Because humans don't have peptidoglycan in their cell walls. c. Because humans and bacteria have different replicating enzymes. d. Because humans and bacteria have different ribosome structures. e. Actually, antibiotics like azithromycin are not selectively toxi