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

The scientific name $Rattus$ $rattus$ is an example of:

Match the items in Column $X$ with Column $Y$ and select the correct option:

Column $X$	Column $Y$
$(1)$ Death	$(P)$ Measure of disorder
$(2)$ Earthworm	$(Q)$ Proponent of New Systematics
$(3)$ Entropy	$(R)$ Process maintaining life continuity
$(4)$ Huxley	$(S)$ Annelida
$(5)$ Reproduction	$(T)$ Process maintaining population size

Match the common names of organisms with their scientific names and select the correct option:

Common Name	Scientific Name
$(1)$ Modern Human	$(W)$ $Pheretima\,posthuma$
$(2)$ Extinct Human	$(X)$ $Zea\,mays\,L.$
$(3)$ Maize	$(Y)$ $Homo\,sapiens\,sapiens\,L.$
$(4)$ Earthworm	$(Z)$ $Homo\,erectus\,L.$

What are '$X$' and '$Y$' in the given figure?

Select the correct option for the following statements:
$(i)$ The basic unit of classification is species.
$(ii)$ Budding is observed in yeast and Hydra/Planaria.