Which of the following correctly describes contrasting features of a plant cell and an animal cell? Plant cells have a cell membrane, and animal cells have both cell walls and a cell membrane.

Plant cells have a large central vacuole that takes up most of the cell's space, and animal cells have many smaller vacuoles.

Plant cells have lysosomes with enzymes, while animal cells have only the Golgi apparatus.

Plant cells have both rough and smooth endoplasmic reticulum, while animal cells have only smooth endoplasmic reticulum.

Keeping in mind the life cycle of bacteriophages, consider the following problem: during the reproductive cycle of a temperate bacteriophage, the viral dna inserts into the bacterial chromosome where the resultant prophage behaves much like a trojan horse. it can remain quiescent, or it can become lytic and initiate a burst of progeny viruses. several operons maintain the prophage state by interacting with a repressor that keeps the lytic cycle in check. insults (ultraviolet light, for example) to the bacterial cell lead to a partial breakdown of the repressor, which in turn causes the production of enzymes involved in the lytic cycle. as stated in this simple form, would you consider this system of regulation to be operating under positive or negative control?