A scientist is observing an organism under the microscope. The organism was found in salt water, is multicellular, and its cells do not have nuclei.

Protists are eukaryotes, which means their cells have nuclei. Since this organism’s cells do not have nuclei, it is not a protist. Being microscopic or found in salt water does not make an organism a protist, and some protists can be multicellular.

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