In the USA, raw sewage (e. g., wastewater from toilets and baths) poses a threat to public health and the health of ecosystems because it contains . Group of answer choices: a) high levels of ozone that can cause a lot of damage to plants and other living tissues b) very little organic nutrients and very little inorganic nutrients c) disease-causing microorganisms and organic and inorganic elements that can be used as nutrients for naturally-occuring microorganisms living in freshwater d) ecosystems aesbosteos fibers that can be ingested by living organisms lead and mercury.

Click an item in the list or group of pictures at the bottom of the problem and, holding the button down, drag it into the correct position in the answer box. release your mouse button when the item is place. if you change your mind, drag the item to the trashcan. click the trashcan to clear all your answers. label the following topographic map. click on a label below the map to select it, and then click on the appropriate box on the map to place the label. (increments for contour lines is 50 ft).

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?

If the nucleus of a cell was removed the cell wouldn’t be able to make proteins because