Are roundworms diploblastic

No, roundworms are not diploblastic; they are triploblastic. They possess three germ layers: ectoderm, mesoderm, and endoderm. This classification places them in the group of animals known as triploblastic organisms, which also includes most other animals, including vertebrates and many invertebrates. Diploblastic organisms, like cnidarians, have only two germ layers: ectoderm and endoderm.