Protozoa, formerly, the name of an animal phylum comprising a large, diverse assortment of microscopic or near-microscopic one-celled heterotrophic organisms (protozoans). The term "protozoan" (or the collective plural "protozoa") continues to be used informally; the organisms are now more commonly placed in any of five phyla in the kingdom Protista.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.
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