Which scientific term is used for a convenient category for the study of organisms?

What is the family of mango $(Mangifera \text{ } indica)$?

Which one of the following animals is correctly matched with its particular taxonomic category?

The study of which of the following is essential for agriculture,forestry,industries,and the conservation of bioresources and their diversity?

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.

Three different genera $Solanum$,$Petunia$,and $Datura$ are placed in the family: