Answer:
Cladograms are used to show the evolutionary relationship between organisms. It is based on the similarities in the physical appearance and phenotype of the organisms.
It cladogram organisms in each clade shows many similarities with each other but not with other clade group. Cladograms are considered to be hypothesis because when new data comes then it can disprove the early evolutionary theory of relationship based on phenetics.
Now the cladogram is based on DNA sequence which is considered to be more reliable to form cladogram than phenotypic distribution of organisms.