Answer: A
Explanation:
Gravity is when you drop something, but in this case you aren’t dropping the ball. It definitely isn’t chemistry because you aren’t changing molecules or anything so that only leaves A which is the most reasonable answer anyways.
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.