Answer:annelids have a complete digestive system
Explanation: bilateral animals are animals whose body can be divided into two mirrored portions of left and right halves.they are said to be bilaterally symmentrical.eg of such animals are flatworms, roundworms,annelids,antropods etc.
Annelids have complete digestive system with a terminal anus..the earthworm for example,feeds through the muscular pharyx,it has an intestine for digesting food and undigested food comes out through the anus.
Flatworms has incomplete digestive system,with only one opening .they have no anus. The undigested food is ejected through the mouth.