One important phylum of kingdom-Animalia of two kingdom system was removed and placed in kingdom Protista of 5 Kingdom system. Name this phylum and give important features.

Explanation

It is the phylum - Protozoa which is characterised by the following:
(i) The organisms are unicellular, eukaryotic and mostly occur in aquatic habitats.
(ii) Most of the protozoans have holozoic (heterotrophic) mode of nutrition.
(iii) Cell walls are absent. However, a few forms have pellicle or hard shells.