The shadow of a tower is always directed toward the North at midday, as shown in the given figure. Where is the tower located?
A)
North of the Tropic of Cancer or 23°N line
B)
Between the Tropic of Cancer and the Equator
South of the Tropic of Capricorn or 23°S line
D)
Between the Tropic of Capricorn and the Equator

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?