Sol-gel theory of locomotion of Amoeba is given by Hymen in 1927 and further supported by Pantin and Mast. Sol-gel theory is most accepted theory for locomotion of Amoeba. The cytoplasm present inside the cell is capable of changing into different forms, i.e. from fluid to solid and vice-versa. When the cytoplasm is in fluid state, it is known as plasmasol and when in solid or gel-like state, it is called as plasmagel. The interchange of these two states (plasmasol to plasmagel) is responsible for movement of amoeba.

Amoeba proteus is ammonotelic in nature.

The adult and harmful stage of Entamoeba histolytica is called trophozoite. Entamoeba histolytica causes amoebic dysentery in humans.

Amoeba shows positive behaviour towards darkness.

Class sporozoa: The locomotary organs are absent.

Ceratium and noctiluca show bioluminescence.

Plasmodium vivax (malaria parasite) completes its asexual part of life cycle in people and the sexual part in the female Anopheles mosquito (Digenetic life cycle). Trypanosam cruzi possesses a digenetic life cycle involving a hematophagous insect vector and a mammalian host.

Balantidium, Giardia and  Trypanosoma: All are internal parasite protozoans. Balantidium is a common intestinal parasite of vertebrates found chiefly in amphibians and mammals. Giardia is found as parasite in the digestive tract of vertebrates. Trypanosoma is an endoparasite, which resides in blood and cerebrospinal fluid of man.

Stichonematic flagella bears a single row of mastigonemes alongside the sheath, e.g. Euglena.

Amoeba was discovered by Sir Ronald Ross.

Trichonympha is a symbiotic flagellate found in the gut of termites and cockroaches.

Reserve food material of Trypanosoma gambiense is in the form of volutin granules. Trypanosoma gambiense reproduce only asexually by binary fission.

Monkeys serve as reservoir host for Plasmodium. Female Anopheles mosquito serves as vector. Gametophytes of Plasmodium are formed in RBC of blood of man. Gametes are formed in lumen of stomach of mosquito.

Duration of exoerythrocytic cycle is 8 days in Plasmodium vivax, while it is 14 - 15 days in Plasmodium malariae. Incubation period is 12 - 14 days in Plasmodium vivax, while it is 20 - 24 days in Plasmodium malariae.

Lobopods: Short, blunt, thick, finger-like outgrowth of ectoplasm with an axial core of endoplasm, e.g. Amoeba. Filopods: Cylindrical thread-like, formed entirely of ectoplasm and radiate from the body in all directions, e.g. Radiolaria. Reticulopods: Filaments form a network of pods, e.g. Polystomella. Axopods: Long, stiff, semi-transparent extensions of cytoplasm with pointed distal ends, e.g. Actinophyrus.