Larry, Darryl, and Jenny are using a gas chromatograph to determine the identity of a chemical sample. They inject the sample into the machine and
then wait to see how long it takes the chemicals in their sample to move
from one end of a tube in the machine to the other end. They use this time
to help them determine the identity of the chemical in the sample. Which is
an unavoidable error in this experiment?
1.Darryl washed the sample with the wrong solvent.
2.Injection of the sample into the machine requires a certain minimum time.
3.Darryl set the temperature on the machine to 350*C instead of 400*C.
4.The tube in the machine is on its seventh run and may contain the remains of old experiments.

Researchers conducted an experiment to identify the effects of three different hand sanitizers on the growth of bacteria. the researchers grew one type of bacteria in twenty-four identical covered petri dishes. then, they opened eighteen petri dishes and applied the three hand sanitizers to six petri dishes each. they left the remaining six petri dishes closed as a control group. when the researchers measured the growth of bacteria two days later, the six dishes that had no hand sanitizer showed the least amount of bacterial growth. the researchers concluded that not using any hand sanitizer would lead to the least bacterial growth. which statement best explains why the researchers’ conclusion was not justified? the experiment tested too many variables. the control group was not treated the same as the experimental group. the sample size of twenty-four petri dishes is not large enough. the single type of bacteria is not adequate to make any conclusions.