Kinases. Kinases add phosphate to molecules, and the modification can serve as a "switch" to turn events in the cell on or off. CDKs or cyclin dependent kinases regulate the cell cycle.
Bats are the only other species that can fly<span />
The lac repressor prevents the lac genes in the DNA of E. coli from being expressed most of the time. The answer to your question is A. I hope this is the answer that you are looking for and it comes to your help.
