Give examples for the following:
$(a)$ Bilateral,dorsiventral symmetry is found in ...............
$(b)$ Worms causing disease elephantiasis is ..............
$(c)$ Open circulatory system is found in ............. where coelomic cavity is filled with blood.
$(d)$ ............... are known to have pseudocoelom.

(A) Liver fluke (Fasciola hepatica) exhibits bilateral,dorsiventral symmetry.
$(b)$ Wuchereria bancrofti (Filarial worm) is the causative agent of elephantiasis.
$(c)$ Arthropods possess an open circulatory system where the coelomic cavity,known as the haemocoel,is filled with blood.
$(d)$ Nematodes (Roundworms) are characterized by the presence of a pseudocoelom,a body cavity that is not completely lined by mesoderm.