The correct option is
C Monerans
The IUCN (2004) stated that more than 1.5 million different species of living organisms have been identified and described by biologists so far. Although, according to the estimates given by Robert May, only 22% of the total number of species has been discovered so far and the global species diversity is likely to be around 7 million.
But these numbers do not include the number of species belonging to Kingdom Monera (prokaryotes). The reasons being -
- The conventional taxonomic methods are unable to identify and classify prokaryotic species
- Many prokaryotic organisms are impossible to culture in vitro and hence cannot be studied properly
Thus biologists are not very certain about the number of existing prokaryotic species. Even if we consider biochemical or molecular characteristics as criteria for distinguishing and identifying the prokaryotic species, the chances are that the numbers might cross millions.
According to the existing inventory on the identified species, more than 70% of all the recorded species are animals and about 22% of the recorded species belong to plants and fungi.
More than 70% of the animal species belong to the class Insecta, the most “species-rich” taxonomic group.
Amongst plants, the highest species diversity is shown by angiosperms (flowering plants), followed by algae, mosses (bryophytes) and ferns (pteridophytes). Fungi are approximately as diverse as the angiosperms and the total number of fungi species in the world is more than the sum total of the number of species belonging to fishes, reptiles, amphibians and mammals.