The answer is; A
The operator site is usually associated with the promoter region of the operon. This region is bound by a repressor. The repressor acts as a physical barrier so the RNA polymerase does not bind to its promoter, or even if it binds, does not proceed to transcribe the genes.
Answer
Nutrition in an Amoeba occurs through a process called phagocytosis
Explaination
where the entire organism pretty much engulfs the food it plans on eating up. ... It involves the ingestion, digestion and egestion of food material. Amoeba does not have any specialized organ for nutrition.
carbon dioxide leaves the body through their respiratory system (lungs)
Proteins are made by the translation of mRNA (via tRNA molecules.) This process is essential for everyday life because proteins perform necessary functions. The protein is your end goal, even though to get there you have to first transcribe DNA to mRNA, then translate mRNA.
