Answer: The correct answer to the question is option WHEN GLUCOSE LEVELS ARE LOW AND LACTOSE IS PRESENT.
Explanation: To start with,Lac operon can be simply defined as a part of the DNA that is under the part of the DNA is manipulated and controlled by the same promoter,they can be found in some prokaryotic cells giving room for regulation over excess synthesis of protein.so simply put,these specific segment of the DNA binds with the segment of the polymerase of RNA so that transcription of the mRNA from the operon genes will be achieved.
Lac operon is also known as lactose operon, it is seen in some enteric bacteria like e.coli where they play a crucial role in coding of genes for those proteins that function in moving lactose into the cystocel and digesting it to form glucose that is used for energy generation. These lac operon are are most active when glucose levels are low and lactose is present,with the low level of glucose, the lac operon can be transcribed to a high level,this is to ascertain that the bacteria only gets to activate the lac operon and can only make use of it,that is using lactose when all the preferred energy source from glucose has been exhausted.
