Members of the Protista kingdom contain multi-celled organisms such as kelp and single-celled organisms such as.

Members of Protista kingdom contain multi-celled organisms such as kelp and single-celled organisms such as Paramecia.

Paramecia are unicellular ciliated protozoan. They are widespread in freshwater, brackish, and marine environments. They are abundant and stagnant in basins and ponds.

The answer is Paramecium.

The Protista kingdom contains eukaryotic organisms that do not belong to the Kingdoms of Fungi, Plantae or Animalia. These organisms could be multicelled or single-celled. Some multicelled organisms of this kingdom are kelp, slime molds, red algae. Among unicelled protozoans, the best known is Paramecium.