Question

Which among the following does not belong to phylum platyhelminthes?
A. Roundworm
B. Planaria
C. Fasciola
D. Echinococcus granulosus

Answer 1

Basically phylum platyhelminthes body is flattened. The species which possesses bilateral symmetry comes under this phylum platyhelminthes. These types of species have three germ layers and don't have any body cavity. This type of species has a soft body and is unsegmented. So the species which have these characteristics belong to phylum.

Complete answer:
Option A: Roundworm body looks hard so it does not come under the phylum platyhelminthes. It also has a body cavity. It has a complete digestive system and a simple nervous system. So it is the correct answer because characteristics aren't related to phylum. Option A is correct.
Option B: Planaria n has three germ layers. It has a single opening digestive tract. It exhibits bilateral symmetry. So it possesses a phylum characteristic. So option B is incorrect.
Option C: Fasciola has the ability to live freely. It also has parasitic adaptations. These characteristics are coming under the platyhelminthes. So option C is incorrect.
Option D: Echinococcus granulosus has three attached segments. It has parasite morphology. It also belongs to the phylum platyhelminthes. So option D is incorrect.

Hence, Option A is the correct answer.

Note:
Important characteristics possessed by the species under the phylum platyhelminthes are they are triploblastic and acoelomate. They may or may not have the cilia. This species is parasitic and few are free living. They don't have any cavities in the body. Around eighty percentages of flatworms are parasitic in nature. Outer layer of the body is soft then they are coming under phylum platyhelminthes.