-Unicellular (or non-cellular)
-They are microscopic
-Tissues are absent
-Specialized part of living material form organelles
-Exhibit all forms of heterotrophism
-Asexual reproduction by binary fission or fragmentation, sexual reproduction by conjugation
-All live in liquid of some kind
i.e aquatic or internal fluids of multicellular animals
e.g Amoeba, Paramecium, Plasmodium
-locomotion is either by cilia, pseudopodia or flagella
-symmetry is present
-excretion or respiration diffusion either
-contractile vacuole for excretion osmoregulation