Who defined species as a group of interbreeding organisms that are reproductively isolated from other such groups?

$Nicotiana$ $sylvestris$ flowers only during long days,while $N.$ $tobacum$ 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 $N.$ $tobacum$ to be separate species?

Through the study of classification,which of the following is true?

How many names are provided in the binomial nomenclature of an organism?

Which of the following terms is related to $Homo$ $sapiens$?

Plants growing in saline and marshy conditions are called