The statement "A researcher intervenes in the diet of one community and not in another and over..." is an example of experiment. This is further explained below.
<h3>What is an experiment?</h3>
Generally, experiment is simply defined as discovery, hypothesis testing, or demonstrating an already-known truth by a scientific technique.
In conclusion, an example of an experiment is "intervened in the nutrition of one group and not another and over..."
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