The model shows the process of evolution at work in a population of aphids with varying amounts of pesticide resistanceSelect ALL of the requirements for evolution to occur A) Sexual reproduction must occur. B) The final population is purely random Genetic variation must exist in the population D Those with the highest pesticide resistance reproduced . E) Only those with the highest pesticide resistance level survived exposure to the pesticide

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?