Question

Blind sac body plan is found in the members of

• A. Platyhelminthes and Aschelminthes
• B. Molluscs and Echinodermata
• C. Porfera and Coelenterata
• D. Coelenterata and Platyhelminthes

Answer 1

Answer: (D)

The digestive system is incomplete with a single opening (blind sac body plan) that acts as anus and mouth. This body plan is observed in Coelenterates and Platyhelminthes.
The digestive system is complete with two openings (tube within tube plan) which behave as anus and mouth separately. This body plan is observed in Aschelminthes to Chordates.