In a local river, a new industrial plant has been increasing the temperature of the water with thermal pollution. The average water temperature increased by 2 degrees Fahrenheit in but has not changed since then.
Which explanation BEST predicts how this change will affect the local fish population in the river?
А
The fish population will stay the same, because the change in water temperature is too small to have an impact.
B
The fish population will increase, because fish reproduce more in warmer temperatures.
С
The fish population will decrease because the pollution will make the water more acidic.
D
The fish population will decrease, because there will be less oxygen in the water.

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?