Which scientific term is used for a convenient category for the study of organisms?

In the binomial nomenclature of an organism,whose name is written in an abbreviated form after the specific epithet?

Match the common name given in column $I$ with their taxonomic category order given in column $II$ and choose the correct combination from the options given below.

Column-$I$ (Common name)	Column-$II$ (Taxonomic category-Order)
$A$. Wheat	$I$. Primata
$B$. Mango	$II$. Diptera
$C$. Housefly	$III$. Sapindales
$D$. Man	$IV$. Poales

Match the taxonomic categories given in column $I$ with their feature given in column $II$.

Column $I$	Column $II$
$A$. Taxon	$I$. Basic unit of classification
$B$. Species	$II$. $A$ taxonomic group of any rank
$C$. Phylum	$III$. Division is the same category in case of plants.
$D$. Genus	$IV$. Category identified based on the aggregates of characters
$E$. Order	$V$. Group of related species

Species are considered as

All taxonomic categories together constitute the..........