Sporozoans are a group of unicellular, parasitic protozoa belonging to the phylum Apicomplexa. They are characterized by their complex life cycles, which often involve multiple hosts and stages, including sporozoites, meronts, and gametocytes. Notable examples include the malaria-causing Plasmodium species and Toxoplasma gondii, which can infect various animals, including humans. Sporozoans are significant in medicine and veterinary science due to the diseases they cause.