What Are The Characteristics/features Of The Phylum Protozoa?

Free living protozoa mostly aquatic, inhabiting fresh and marine waters and damp places. Parasitic and commensal Protozoa live over or inside the bodies of animals and plants.
The including animals are small size, usually microscopic animals, originally not visible without a microscope.

These are simplest and most primitive of all animals.Body unicellular, containing one or more nuclei and organelles, with little or no histological differentiation into tissues and organs.

Solitary or form loose colonies in which individuals remain alike and independent.
Body symmetry none, bilateral, radial or spherical.Body is naked or bounded by a pellicle and provided often with simple to elaborate shells or exoskeletons.Cell which forms usually constant varied in some, while changing with environment or age in many.Locomotory organs are finger –like Pseudopodia or whip like flagellated or hair like cilia or absent.

Nutrition may be holozoic holophytic, saprophytic or parasitic.
Respiration is through general outer surface of the body.
Excretion is through general surface or through contractile vacuoles which also serve for osmo-regulation.Reproduction is asexually by binary or multiple fission. Encystment is commonly occurs to help in dispersal as well as to resist unfavorable conditions of food and temperature.

Reproduction in protozoa

Habitat:- they are either fresh water or marine or found in moist places
organizations:-in most of the protozoans , the cytoplasm is differentiated into outer ectoplasm and inner ectoplasm.
Body covering :- the body of some protozoa like amoeba is covered by thin plasma membrane

Unicellular
Requires moisture
Reproduce asexually