Parasitic Flatworms: Taenia & Fasciola — NEET Biology

Correct answer: B — S2, S3 and S5

The core concept tested is the general and specific characteristics of Phylum Platyhelminthes. S1: Incorrect. While most are endoparasites, free-living forms like Planaria exist. Not all obtain nutrients by absorbing them directly through their body surface, as free-living forms feed differently. S2: Correct. Platyhelminthes have an incomplete digestive system, with a single opening serving as both mouth and anus. S3: Correct. Taenia and Fasciola are examples of parasitic flatworms, and parasitic forms typically possess hooks and suckers for attachment. S4: Incorrect. While flame cells indeed aid in osmoregulation and excretion, sexes are not separate in Platyhelminthes; they are hermaphrodite (monoecious). S5: Correct. Platyhelminthes exhibit organ level of organisation, and Planaria is specifically mentioned for its high regeneration capacity. S6: Incorrect. Development in Platyhelminthes is generally indirect, involving many larval stages, not direct. Therefore, statements S2, S3, and S5 are correct. Recap: Platyhelminthes can be free-living or parasitic, have an incomplete digestive system, use flame cells for osmoregulation/excretion, are hermaphroditic, show indirect development, and exhibit organ level of organisation.