Nearly 50% of water sources in the united states are believed to be polluted. select the best answer from the choices provided t f

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?

The diagram shows the layers of earth. convection currents in which region influence the movement of tectonic plates

Explain what a zygote is. use the terms egg cell, sperm cell, and fertilization in your explanation.