Question

The blind sac body plan is applicable to members of phylum......... belonging to the kingdom Animalia.

• A. Porifera
• B. Annelida and Arthropoda
• C. Cnidaria and Platyhelminthes
• D. None of the above

Answer 1

The correct option is C Cnidaria and Platyhelminthes

• In a blind sac body plan, the sac-like body is linked with a digestive cavity that opens to the outside by only one aperture.
• This single opening serves as the mouth as well as anus. The cells are more specialized with the division of labour.
• This type of body organization is exhibited by the Coelenterata (anemones, jellyfish, corals, hydras), Ctenophora (comb jellies), and Platyhelminthes (flatworms).

Thus, the correct answer is option C.