Bilaterally symmetrical and acoelomate animals are exemplified by

Step-by-step solution

Coelom: The body cavity; which is lined by mesoderm is called coelom. Coelomates: If coelom is present, the animal is called coelomate, e.g. Annelids, Molluscs, Arthropods, Echinoderms, Hemichordates and Chordates. Pseudoceolomates: If the body cavity is not lined by mesoderm, but the mesoderm is present as scattered pouches in between the ectoderm and endoderm, the animal is called pseudocoelomate, e.g. Aschelminthes. Acoelomates: When the body cavity is absent, the animal is called acoelomate, e.g. Platyhelminthe