Question

How do flatworms, roundworms, and segmented worms differ from each other?

Answer 1

Hint: The flatworms, roundworms, and segmented worms all are small creeping invertebrate species that do not show any presence of limbs and bones.

Complete answer:
Although flatworms, roundworms, and segmented worms all are worms but they all belong to different phyla. Flatworms belong to the phylum Platyhelminthes and the roundworms belong to the phylum Nematoda that is also known as the phylum Nemathelminthes or the phylum Aschelminthes and the segmented worms belong to the phylum Annelida.

The cavity that is present in the body is present between the alimentary canal and the wall if the body is known as the coelom. The flatworms are acoelomates and do not have any coelom or cavity in their body whereas the roundworms have pseudo coelom also known as the false coelom and hence are known as pseudocoelomates and the segmented worms have true coelom and hence are known as coelomates.
The roundworms and flatworms have an excretory system but they do not have any separate closed circulatory and respiratory systems whereas the segmented worms have specialized circulatory and respiratory systems.

Note: All these worms show a lot of difference in their structure, their internal organs, etc but yet they show some similarities. Flatworms, roundworms, and segmented worms all are bilaterally symmetrical and can be divided into two halves which are similar to each other only when cut in one plane and these worms are either free-living or it can also live as a parasite.