All the unicellular eukaryote are grouped under the Kingdom
A) Protista
B) Protozoa
C) Fungi
D) Monera

Answer Verified Verified
Hint: The kingdom consists of the most primitive eukaryotic form of life which is unicellular which neither prokaryotic nor advanced eukaryotes. They advanced cells having a variety of membrane bound structure and a definite nucleus.

Complete Answer:
To solve this question we have to know the characteristics of eukaryotes and also the classification of organisms.
Robert Whittaker classified the organisms into 5 kingdoms namely- Monera, Protista, Plantae, fungi and Animalia.

1) Kingdom Monera comprises unicellular organisms which lack definite nucleus hence are categorised under prokaryotes. Example Bacterias.
2) Kingdom Protista comprises organisms which are neither plant, animal nor fungi. They are mostly unicellular, free living and also in live colonies. They have a complex cell structure with definite nuclei.. Some Protists are also multicellular which resembles plants in function but differ from them in terms of cellular complexities. Kingdom Protista is classified into Protozoa, Chrysophytes, Euglenoids, Dinoflagellates, slime mould.
3) Kingdom Fungi and Plantae comprises multicellular organisms which have definite nucleus and cell walls. Hence are categorised under Eukaryotes.
4) Kingdom Animalia comprises multicellular organisms which have a definite nucleus but do not have a cell wall. Hence are categorised under Eukaryotes.
Protozoa is a phylum comprising unicellular eukaryotic organisms comes under the kingdom Protista.

Thus the answer of the above question is (A).

Protista as it is a kingdom of eukaryotic unicellular organisms whereas Protozoa are a phylum of unicellular organisms under the kingdom Protista.

Note: Most organisms in the kingdom Protista are aquatic. They are found everywhere where water is present even in human beings. They can be autotrophic like plants or heterotrophic like fungi and animals. They cannot be classified as plants although they resemble plants but lack cellular complexity of Kingdom Plantae. They do not have a particular shape. Locomotion is through cilia, flagella or pseudopodia.