Nematodes are roundworms that have tubular digestive systems with openings at both ends. Annelids are segmented worms that are bilaterally symmetrical and have parapodia for locomotion. Flatworms are soft-bodied invertebrates with one opening for their digestive cavity, so food cannot be processed continuously.

3. (NEMATODE)
 round worms
 difficult to distinguish
 nematodes have tubular
digestive systems with
openings at both ends

4.  ringed worms or
segmented worms
(ANNELID)
 are bilaterally symmetrical
, triploblastic, coelomate,
invertebrate organisms
 They also
have parapodia for
locomotion

5. (FLATWORM)
 are a phylum of relatively
simple bilaterian,
unsegmented, soft-
bodied invertebrates.
 The digestive cavity has only
one opening for both
ingestion (intake of nutrients)
and egestion (removal of
undigested wastes); as a
result, the food cannot be
processed continuously.

6. (FLATWORM)
 are a phylum of relatively
simple bilaterian,
unsegmented, soft-
bodied invertebrates.
 The digestive cavity has only
one opening for both
ingestion (intake of nutrients)
and egestion (removal of
undigested wastes); as a
result, the food cannot be
processed continuously.