Based on the methods used to separate the substance into its parts is substance U is a mixture because physical methods were used to separate its parts; option D.
What are separation techniques?
Separation techniques are techniques employed in the separation of mixtures of substances.
Mixtures are substance made up of two or more components physically joined together.
Considering the substance which is being separated, the separation techniques employed are physical separation techniques, hence the substance is a mixture.
In conclusion, physical separation techniques are employed in the separation of mixtures.
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