What does '$X$' represent in the given figure?

What should a student of taxonomy $NOT$ possess?

Petroleum is derived from the words 'Petra' meaning rock and 'Oleum' meaning oil. The words 'Petra' and 'Oleum' are:

Match the following columns:

Column-$I$ (Genus)	Column-$II$ (Family)
$i$. $Zea$	$a$. $Blattidae$
$ii$. $Helianthus$	$b$. $Poaceae$
$iii$. $Pheretima$	$c$. $Asteraceae$
$iv$. $Periplaneta$	$d$. $Megascolecidae$

Which of the following $statement(s)$ is/are correct?
$(i)$ Classification is providing standardized names to organisms such that a particular organism is known by the same name all over the world.
$(ii)$ Taxonomy is the correct description of an organism and its recognition in its scientific name.
$(iii)$ The system of naming with two components (binomial nomenclature) was proposed by Carolus Linnaeus.
$(iv)$ Zoological names are based on the International Code for Zoological Nomenclature $(ICZN)$.

In which text is the classification of organisms mentioned?