Binomial nomenclature means

$Nicotiana \ sylvestris$ flowers only during long days and $N. \ tabacum$ flowers only during short days. If raised in the laboratory under different photoperiods,they can be induced to flower at the same time and can be cross-fertilized to produce self-fertile offspring. What is the best reason for considering $N. \ sylvestris$ and $N. \ tabacum$ to be separate species?

The scientist who proposed the binomial nomenclature system is.......

The scientist who classified plants based on their habitat is .......

The complete name of a plant in binomial nomenclature has

Linnaeus classified plants into $24$ groups based on which of the following?