Darwin collected and studied a variety of fossils. The fossils provided clues to ancient organisms. As Darwin concluded, how did ancient organisms compare to modern species? A. The ancient organisms were identical to modern species.
B. The ancient organisms were larger or smaller than modern species, but otherwise identical.
C. The ancient organisms were similar to modern species, but differed in several ways.
D. The ancient organisms were very different from modern species, and lacked any significant similarities.

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?

Penelope studies how the structure and function of the nervous system is related to behavior. she is a psychologist

Which zone within the open-ocean zone is home to the most organisms? deep zone surface zone intertidal zone transition zone