Which of the following statements about the global phosphorus cycle is true? a) Some phosphorus applied to crops as fertilizer leaves the terrestrial subsystem.
b) The bulk of Earth's phosphorus is found in deep ocean waters.
c) Fertilizers have decreased phosphorus availability in terrestrial ecosystems.
d) The mining of phosphate ore is an insignificant source of phosphorus for fertilizers.

Match the examples to the correct level of organization. 1. system level roses, snakes, puppies 2. organism level roots, stamens, leaves 3. tissue level bone, cartilage, blood 4. organ level heart, veins, arteries

What is the difference between an igneous, sedimentary and metamorphic rock

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?