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.
The guinea pig and the raccoon are both members of :
The eukarya domain, the kingdom of animals, the chordates and the mammal class.
After the level of class (Mammalia), they start to belong to different groups.
The guinea pig belongs to rodents and the raccoon belongs to the carnivores.
The pectines on a male scorpion is longer because they also use it to find a female to mate with.
They are called sacromeres.
