Which best describes a difference between prokaryotic cells and eukaryotic cells?

Which of the following would most likely be key to gathering evidence that the rna world hypothesis is valid? creation of suitable environments for long-term study of single-celled organisms simulation of early earth conditions and long-term study of the resulting molecules development of a system for studying the microsphere's ability to absorb additional molecules categorization of the different specific conditions that result in the development of microspheres

How does friction with the atmosphere affect the speed of an artificial satellite

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?