Any of the eukaryotic, unicellular organisms of the former kingdom Protista, which includes protozoans, slime molds, and certain algae. The protists now belong to the kingdom Protoctista, a new classification in most modern taxonomic systems.

• 原生生物原生生物界中的真核单细胞有机体中的任何一种，包括原生动物、粘菌和某些藻类原生生物现在属于原生生物界，它是大多数现代分类系统中的一个新的类别