Answer :

porifera                                       coelenterata

extenal skeleton is present         external skeleton is absent
there are pores all over their       only one opening
body    
eg: spongilla                               eg:hydra
                                                                                                        
platyhelminthes                        nematoda 

dorsally flattened body             cylindrical sahape
no body cavity                          pseudo coelomate
eg:tape worm                            eg:round worm
porifera :-
- organization level is cellular 
- asymmetrical 
- germinal layers N/A

Coelenterata ( cnidaria ) 
- organization level is tissue 
- radial symmetry 
- germinal layers diploblastic 


platyhelminthes :-
 - coelom is acoelomate 
 - hermaphrodite ( both sex are found in same animal )


Nemathelminthes :-
- pseudocoelomate 
 - monoecious ( sexes are separated ) 

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