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

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

As we move from Kingdom to Species in the taxonomic hierarchy,the number of common characteristics among organisms .............

Which of the following taxonomical ranks contains organisms that are least similar to one another?

Which taxonomic category covers the largest number of organisms?

$A :$ Scientific names for plants have been standardized through $ICBN$.
$R :$ Naming system which uses three-word format was given by Linnaeus.