Amoeba is a single-celled organism belonging to the kingdom Protista. It moves and feeds using extensions of its cell membrane called pseudopodia ("false feet"). Amoebas live in water, moist environments, or inside other organisms, and reproduce asexually by binary fission. Some are free-living, while others are parasitic and can cause diseases like amoebiasis.

Amoebas are typically classified into four main types based on their habitats and structures:

Free-living Amoebas – Live in water or soil; e.g., Amoeba proteus.

Parasitic Amoebas – Live inside hosts and may cause diseases; e.g., Entamoeba histolytica (causes amoebiasis).

Testate Amoebas – Possess a protective outer shell (test); e.g., Arcella.

Marine Amoebas – Inhabit saltwater environments; often have complex shells;