Posted by ROSHAN B.S on Aug. 25, 2014, 7:24 p.m.
In some biological taxonomy schemes, Protozoa are a diverse group of mostly mobile unicellulareukaryotic organisms,[1] but the term is no longer used in modern taxonomy.
Historically, protozoa were defined as unicellular protists with animal-like behaviour, such asmovement. Protozoa were regarded as the partner group of protists to protophyta, which have plant-like behavior, e.g. photosynthesis. The term protozoan has become highly problematic due to the introduction of modern ultrastructural, biochemical, and genetic techniques, which have showed that the group does not form a clade as required by modern classifications. Modern unicellular clades within Eukaryotes which may be viewed as approximately collectively replacing the class of protozoa include: Excavata, Amoebae, Chromalveolata and Rhizaria.