Question

The tube within tube plan is not present in ...........

• A. Taenia
• B. Pheretima
• C. Leech
• D. Ascaris

Answer 1

The correct option is C Leech

• Tube within a tube plan is the development of a fluid-filled cavity between the outer body wall and the digestive tube.
• It is seen in acoelomate, pseudocoelomate and coelomate animals.
  

A. Taenia is a genus of tapeworms which are acoelomates.

B. Pheretima is a genus of earthworms which are true coelomates.

C. Leeches are segmented worm-like animals belonging to the phylum Annelida which are schizocoelomates.

D. Ascaris is a genus of parasitic roundworms pseudocoelomates.

• So, the correct answer is 'Leech'.