Two similar holotypes are called

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.

$A :$ Members of a species are reproductively isolated from the members of other species.
$R :$ Species is the basic taxonomic category.

Each category in the classification of organisms forms a .....

Identify the taxon from the following.

Assertion : Taxon and category are different things.
Reason : Category shows hierarchical classification.