Question

Round worms differ from flatworms in having

• A. Pseudocoelom
• B. Circulatory system
• C. Longitudinal nerve cords
• D. Flame cells

Answer 1

The correct option is A Pseudocoelom

Roundworms belong to the phylum Nematoda, while flatworms belong to the phylum Platyhelminthes.
Roundworms have bilateral symmetry and three-tissue layer construction. In contrast with flatworms, roundworms have a fluid-filled cavity, called as the pseudocoelom and a digestive tract with two openings. Pseudocoelom is called so as it is not completely lined with mesoderm and flatworms are acoelomate.

So, the correct answer is 'A'.