Question

The basic unit of taxonomy is
A. Species
B. Genus
C. Kingdom
D. Family

Answer 1

Hint: Taxonomy is the branch of biology that is connected with identification, nomenclature, and classification of organisms. The term taxonomy was coined by de Candolle in the year 1813.

Complete answer:
The category of scientific classification is called a taxon. A taxon is any level of grouping of organisms, e.g mammals, roses, crucifers, poppies, etc. Carl Linnaeus is called as the father of taxonomy who formulates and adheres to a uniform sequence of arrangement of taxonomic categories in descending order during the classification of an organism. The hierarchy was first given by Linnaeus who used only five Categories-class, order, genus, species, and variety. The last one was discarded and three added so that now there are several obligate categories- Kingdom, division (phylum), class, order, family, genus, and species. Sub and super-categories are interpolated according to requirements, e.g superclass, subclass.
Species is a natural population or group of natural populations of individuals that are genetically distinct and reproductively isolated with similar essential morphological traits. Species are also a genetically closed system because its members do not interbreed with members of other species is the lowest or basic taxonomic category. Interbreeding can not be applied for the delimitation of species in the case of prokaryotes and some protists which lack sexual reproduction. Only morphological characters are used in such cases. Where even morphology can not be used, biochemical analysis is employed. At times, hybridization occurs between two different species. These produce sterile hybrids, e,g mule (female horse and male donkey), Hinny (female donkey and a female horse). Fertile interspecific hybrids are also known, e.g tigon, the liger. Viable hybrids are commonly sturdier than either parent. The phenomenon is called hybrid vigour.
Genus is an assembly of related species that evolved from a common ancestor and have certain common characters called correlated characters. A genus having only one species is monotypic. Others are polytypic.
The kingdom is the highest taxonomic category, for example, kingdom plantae, Kingdom Animalia.
Family is a taxonomic category that includes one or more related genera. All the genera of a family have some common or correlated features. In plants the family ends in the suffix-aceae and subfamily in-oideae while in animals the suffixes are –ieae for family,-inae for sub-family, -ini for the tribe (between subfamily and genus), and –oidea for the subfamily.

So, the correct answer is option A i.e. Species.

Note:
Genus is a rank in the biological classification (or taxonomy). Genus is the first order category above the species level. It is a group of species, which are related and have fewer characters in common as compared to species.