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Scientific Inquiry — Unit test Answers

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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?

A
The experiment tested too many variables.
B
The control group was not treated the same as the experimental group.
C
The sample size of twenty-four petri dishes is not large enough.
D
The sample size of twenty-four petri dishes is too large.
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Density is mass per unit of volume. Which pair of lab instruments would a student use to measure the density of seawater?

A
a caliper and a flask
B
a stopwatch and a beaker
C
a balance and a beaker
D
a meter stick and a temperature probe
23

The graph shows a student’s data from an investigation about plant growth in five plants of the same type.WeekAvg. Plant Height (cm)Avg. Growth (cm)02NA1312633934145Which is the best way to display this data for analysis?

A
Place the data in a chart that includes individual measurements before averages were calculated so the information is more complete.
B
Transfer the data into a pie chart with five sections, one for each week, that are sized based on plant growth for that week.
C
Use the first column of data for the x axis the second column for the y axis and plot the data in a line graph to show the growth trend.
D
Use the first column of data for the y axis the second column for the x axis and plot the data in a line graph to show the growth trend.
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Studying the folding patterns of protein molecules can help microbiologists better understand cellular processes as well as some diseases, such as Alzheimer’s, that are caused by proteins that have misfolded. The folding of these complicated molecules can be simulated on computers, but it takes a lot of processor power and time for even expensive supercomputers to do this. A group of researchers at Stanford University developed software that can be used to distribute the processing of data to anyone who is willing to donate time on their idle personal computers. As a result, the researchers have been able to achieve protein-folding simulations that are far better than those other computing methods have done. Which statement best describes the work of these researchers?

A
The work is not scientific because the data are not processed in one location.
B
The work is not scientific because the simulations are not reproducible.
C
The researchers applied creativity to solve a problem in running an experiment.
D
The researchers used only well-established scientific techniques.
25

Which statement best explains why the development of a new area of science can lead to changes in a theory?

A
A new area of science attracts new scientists who study old theories for flaws.
B
A new area of science promotes experimentation from a different point of view.
C
A new area of science allows old theories to be reworded using new terminology.
D
A new area of science encourages scientists to replace old theories with modern ones.

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