Question ID:PT74 S1 Q15 Passage:Researcher: Salmonella bacteria are a major cause of illness in humans who consume poultry. Young chicks that underwent a new treatment exhibited a lower incidence of Salmonella infection than did untreated chicks, although one week after the treatment was administered the treated chicks had higher concentrations of a variety of bacteria than did untreated chicks. Stem:Which one of the following, if true, most helps to explain the concentrations of bacteria one week after the treatment? Correct Answer Choice:EChoice A:The new treatment takes several weeks to administer. Choice B:Levels of Salmonella bacteria in young chicks are generally not high to begin with. Choice C:Most chicks develop resistance to many harmful bacteria by the time they reach adulthood. Choice D:The untreated chicks experienced a higher incidence of illness from infection by bacteria other than Salmonella than did treated chicks. Choice E:The bacteria found in the treated chicks were nonvirulent types whose growth is inhibited by Salmonella bacteria.