How useful is the study of the nature of body cavity and coelom in the classification of animals?

How useful is the study of the nature of body cavity and coelom in the

1.	How useful is the study of the nature of body cavity and coelom in the classification of animals?
Answer» The nature of coelom gives important clue for classification of animals. The absence of coelom means that the animal has not developed a division of labour for various biological activities. On the other hand, the presence of coelom shows further evolution from simple to more complex organism.