1 A team of scientists prepares to study the flow of a river through a desert canyon for the next 10 years. The scientists think that the water is contributing to weathering and erosion of the canyon. What kind of data should the scientists collect as evidence to support their explanation?
A
Measure the water levels to see if less water can make the same changes in the canyon.
B
Record the measurements of distinct parts of the canyon to see if those areas change over the years.
C
Measure the temperature of the water to see if the water temperature becomes slightly warmer or cooler.
D
Take samples of the water that is flowing into the canyon. Test the samples in a lab to see whether the water and particles that make it up change over the allotted time.

Why do bacteria thrive even in hostile environments

How is ribosomal rna useful as a molecular clock? a. a large portion of the dna ring is not vital to structure or function, allowing it to accumulate neutral mutations. b. its rate of mutation increases over time as organisms continue to evolve and differentiate from each other. c. a slow mutation rate makes it useful for determining evolutionary relationships between ancient species. d. it is only found in select organisms, making it easier to compare relationships between species that have it.

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?