By binding to an enhancer, an activator can interact with ( …

By binding to an enhancer, an activator can interact with (                                ) nearby the core promoter of a eukaryotic gene to covalently modify histones, thereby promoting the formation of the preinitiation complex.  

On its chromosome, an E coli cell has the genotype lacI+ lac…

On its chromosome, an E coli cell has the genotype lacI+ lacO- lacZ+ lacY+ lacA+.  It has an F’ factor with the genotype lacI+ lacO+ lacZ+ lacY+ lacA+.  What is the expected level of expression of the lac operon genes (lacZ+ lacY+ lacA+) in the absence of lactose?