What is '$P$' in the given figure?

Which book has most influenced the approach of taxonomists?

Linnaeus's classification was primarily based on ............ .

Who wrote the book titled "Théorie élémentaire de la botanique"?

The term $Taxon$ for plants was given by .........

Select the correct statements $(i-iv)$ regarding taxonomic categories.
$(i)$ Each step or rank in the hierarchy is called a taxonomic category.
$(ii)$ Species is a group of individual organisms with fundamental similarities capable of breeding among themselves.
$(iii)$ Taxonomic studies of all known organisms have led to the development of common categories like kingdom,phylum or division,class,order,family,genus and species.
$(iv)$ Lower the category,greater is the difficulty of determining the relationship to other taxa at the same level.