Final answer:
Phylum Nematoda belongs to Eumetazoan, and exhibits Bilateral symmetry, Triploblastic tissue layers, and Protostome development. They are part of the Ecdysozoa clade and have a Pseudocoelomic body cavity formed by Schizocoelic development.
Step-by-step explanation:
Description of Phylum Nematoda
Phylum Nematoda can be categorized using the following traits: They are Eumetazoan, since they are 'true animals' with tissue organization. These organisms exhibit Bilateral symmetry, dividing them into symmetrical right and left halves.
Nematodes are Triploblastic, forming three germ layers during embryonic development: ectoderm, mesoderm, and endoderm. They are also considered Protostomes, based on their embryonic development pattern. Additionally, as members of the Ecdysozoa clade, they undergo molting called ecdysis.
Nematodes have a Pseudocoelomic body cavity, which is not fully lined by mesoderm. Their body cavity is formed by the splitting of the mesoderm or Schizocoelic development.
Characteristic features of nematodes include tubular morphology with a circular cross-section, a complete digestive system, and a simple excretory system.
Some species are free-living whereas others are parasitic. They have a cuticle that must be molted during growth, which is a defining characteristic of the Ecdysozoa.