Protists are a diverse group of eukaryotic microorganisms that do not fit into other kingdoms like plants, animals, fungi, or monera. Traditional classifications divided protists into animal-like protozoa, plant-like protophyta, and fungus-like slime molds and water molds based on superficial similarities. Modern classifications attempt to create monophyletic groups based on ultrastructure, biochemistry, and genetics. Protists exhibit different types of feeding, reproduction both sexually and asexually or through complex life cycles, and some are important pathogens or can be used to fight diseases and reduce insect populations.