Answer:
The arm that was not sprayed with anything
Explanation:
The control group would be <u>the arm that was not sprayed with anything</u>.
<em>The control group during an experiment is a group that forms the baseline for comparison in other to determine the effects of a treatment. The control group does not include the variable that is being tested and as such, it provides the benchmark to measure the effects of the tested variable on the other group - the experimental group. In this case, the experimental group would be the arm that was sprayed with the repellent.</em>
Answer:
MIXTURE
Explanation:
A mixture is a substance composed of a combination of other different substances. These component(s) of a mixture are physically combined, meaning that there is no chemical linkage between the individual components/constituents of a mixture.
This is the case of the gravel described in this question. The components of gravel can be separated using physical means because they are not chemically bonded to one another, hence, no chemical reactions are needed to separate different parts of gravel into pure substances. This makes gravel a MIXTURE.
The minimum energy required to excite a hydrogen atom from its lowest energy level is 10.2 eV.
<h3>What is excitation?</h3>
The term excitation has to do with the promotion of an electron from a lower to a higher energy level.
In this case, we are dealing with the hydrogen atom having only one electron. Thus, the minimum energy required to excite a hydrogen atom from its lowest energy level is 10.2 eV.
Learn more about energy level:brainly.com/question/17396431
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Answer: A different group of scientists using different methods.
