Give scientific reasons :
The phylogenetic relationship is useful as a criterion for classification. 

Explanation

Phylogeny is the evolutionary history of an organism. It shows the true kind of relationship in organism. This relationship are not clear in all cases. We can get some information from fossil record but it is not enough. Hence the phylogenetic relationships are ascertained from morphology, cytology, genetics, physiology and biochemistry for correct classification of the organisms.