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The correct answer is e. Bacteria prefer to consume glucose first. Bacteria cannot grow in lactose unless the enzyme B-galactosidase is transcribed in order to cleave the glycosidic bonds in lactose (lactose is a disaccharide consisting of the sugars galactose and glucose). In order for B-galactosidase to be produced (which is on lac Y), RNA Polymerase must bind to lac O. In order for RNA Polymerase to bind, the repressor must not be able to bind. The depressor cannot bind when a molecule of lactose is bound to it.
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