(2) The drawing (for item 2) shows a mountain stream flowing over a waterfall. An aerial photograph taken 50 years ago shows that the waterfall today, compared to its previous position, has “retreated” upstream about 250 feet. What best accounts for the retreating of the waterfall? b) glacier action during winter (2) motion in the Earth's crust tidal activity (41) meandering stream action (5) erosion of the stream bed

Photosynthesis converts light energy to chemical energy. which molecules are the end product of this transformation of energy in this reaction?

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?

Which are characteristics of flukes? check all that apply. a they are free living. b they are a type of flatworm. c they reproduce sexually. d they have eyespots. e they are segmented.