If a botanist has to nomenclate a similar species,he will use

Assertion $(A)$: $A$ taxonomic category composed of a group of related genera is called a family.
Reason $(R)$: The family $Blattidae$ includes various species of pigeons and doves.

$X$ being a higher category is the assemblage of families which exhibit a few $Y$ characters. The $Z$ characters are less in number as compared to different genera included in a family. Identify $X$, $Y$, and $Z$.

What is the scientific name of potato?

What do we learn from the identification of individuals and populations?

Which of the following represents the correct sequence of taxonomic categories in descending order of variation?