A scientist is studying specialized cells that help pump blood. Which cells is she most likely studying? neurons, which are a type of muscle cell
cardiac cells, which are a type of muscle cell
epithelial cells, which are a type of blood cell
white blood cells, which are a type of blood cell

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?

20 how are energy cycles and growth cycles related?

Injuries in the environment are a result of