Answer:
Based on their body structure, flatworms and rotifers were not thought to be closely related. However, bilateral symmetry and body texture showed that they are a soft-bodied group.
Explanation:
- Flatworm belongs to phylum Platyhelminthes and Rotifera belongs to phylum Rotifera.
- Their body structure may be different but both of them have a bilaterally symmetrical body.
- Both are aquatic animals.
- Flatworm is made up of ectoderm endoderm and mesoderm and has circular and longitudinal muscles. Rotifera is made up of skeletal and visceral muscles. So, they are soft-bodied animals.