Some people believe that applying lavender oil will make you less stressed by causing the brain to release serotonin. To test this, scientists set up an experiment with three groups. The first
reported their stress levels on a scale of 1-10 at the beginning and ending of a two hour period.
At the beginning of the two hour period, they applied simple water droplets to themselves. The
second and third groups reported their stress levels at the beginning and ending of the same
two hour period, but applied two different amounts of lavender oil to themselves at the
beginning of the two hours.

How do you date a sample of rock that you suspect as being one of the earliest on earth

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?

Match the description of each organism to the appropriate category