According to the rules of biological nomenclature, which name is written in an abbreviated form?

$A :$ Two plants $A$ and $B$ are treated as two taxonomic species.
$R :$ Both $A$ and $B$ are different in correlated characters.

Taxonomic hierarchy refers to

Four statements are given below regarding the nomenclature of organisms. Which two statements are correct?
$(1)$ The first name denotes the species and the second denotes the genus.
$(2)$ $A$ species name used for one organism cannot be used for another organism.
$(3)$ Each word in a handwritten scientific name must be underlined.
$(4)$ It is mandatory to write the sub-species name after the species name for every organism.

Which of the following is the correct ascending order of different taxonomic categories used in plant classification?

What is a Kingdom?