Which of the following is a characteristic of the nematodes?

Members of the phylum Nematoda are elongated, triploblastic, unsegmented worm-like pseudocoelomates that show bilateral symmetry. 

Triploblastic animals have three primary embryonic germ layers i.e., the ectoderm, mesoderm, and endoderm. The different tissues and organs of the animal's body differentiate from these three primary germ layers.