Which describes a non-point source of pollution?
A. accumulation of oil in a stream next to a gasoline station
B. chemical spill in a river next to a manufacturing complex
C. runoff from a road into a nearby stream
D. liquid fertilizer flowing from a barrel into a stream

Which of these resources is used worldwide to make construction products, pottery, and porcelain

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?

How do living things obtain phosphorus