The only taxonomic category that has a real existence is...

$A$ species can be considered as . . . . . . .

Which of the following groups of organisms can interbreed?

Which option provides the correct answers to the following questions regarding a species?
$(i)$ What kind of offspring is a species capable of producing?
$(ii)$ What kind of individuals are included in a species?
$(iii)$ In some cases,what name is written after the species name?
$(iv)$ What is the species name of sunflower?

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.

$A$ group of organisms with fundamental similarities is known as: