Question

The organisms which are single-celled have no chloroplast or nucleus is classified under
(a)Kingdom Protista
(b)Kingdom Monera
(c)Kingdom Fungi
(d)None of the above

Answer 1

Hint: The organisms that do not contain a true nucleus or any membrane-bound organelles like chloroplasts are known as prokaryotes or prokaryotic organisms. They are the oldest known microorganisms found on the Earth's surface.

Complete answer:
Kingdom Monera consists of prokaryotic organisms that do not contain any chloroplasts, a well-defined nucleus, or membrane-bound organelles. The kingdom was distinguished from other kingdoms by the fact that all prokaryotes come under Kingdom Monera and it is a part of the five-kingdom classification proposed by R. H. Whittaker.

Additional Information:
Kingdom Monera- These are prokaryotic organisms that do not contain a true nucleus and are the oldest known microorganisms. They also lack membrane-bound organelles like mitochondria, lysosome, endoplasmic reticulum, chloroplast, etc. Archaebacteria, eubacteria, Cyanobacteria are examples of Monera.
Kingdom Protista- These are eukaryotic i.e. contain membrane-bound nucleus and organelles and unicellular. These live in water, a damp terrestrial environment, and also as parasites. They can be both autotrophic and heterotrophic. Symbiosis, parasitism characteristics are also observed in these. Some examples of protists are dinoflagellates, euglenoids, chrysophytes, etc.
Kingdom Fungi- These are heterotrophic organisms and eukaryotic in nature i.e. they contain a true nucleus and membrane-bound organelles. They perform extracellular digestion for living. The sources of their nutrition can be in the form of simple sugars, complex carbohydrates, or polypeptides.
Therefore, the correct answer is "Kingdom Monera".

Note: Ernst Haeckel in 1866 proposed that the taxon monera should be a phylum which later on got elevated to the rank of Kingdom by Edouard Chatton. Later in 1969, Robert Whittaker accepted it in the five-kingdom classification system. This kingdom is often divided into two domains namely archaea and bacteria and sometimes with a third domain eukarya. The members of this kingdom are known as "Moneran".