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Researchers must utilize a control group in a scientific study because <span>it is important to show that between two groups that were similar from the beginning of the study, the one that received the manipulation is the one that changes. Note that the control group is the group in the experiment that does not receive manipulation by the experimenter and is thus used as basis for how the other test subjects changed. </span>
Answer: Well the railroads made it possible for urban cities to get food and fuel other needed materials.
Explanation: When railroads came in it allowed more things to come and go through cities making it perfect for distributing needed goods for the people who lived there and nearby.
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