Marcel conducts an experiment to test which stain remover works best on mustard stains. He wants to make sure that he does not make mistakes and has correct data in his experiment.What should Marcel do to make sure that his data are correct?

Marcel should repeat the experiment several times while keeping the same variables and constants. Repeated trials help show whether the results are consistent and reduce the effect of random mistakes. Choice D, repeat the experiment several times with the same variable and constants, is the best way to check that his data are reliable.

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