Which of the following is a characteristic of the Annelida phylum?

The correct answer, earthworms, is indeed a characteristic representative of the Annelida phylum. Annelids, also known as segmented worms, are defined by their segmented bodies, which is a distinctive feature of this phylum. These segments are often externally visible and are separated by septa, allowing for greater flexibility and mobility.

Annelids exhibit a body plan that includes a coelom, which is a fluid-filled body cavity lined by mesoderm, providing space for the development and organization of internal organs. They possess a well-developed nervous system and a closed circulatory system, which distinguishes them from many other invertebrates.

In contrast, clams belong to the Mollusca phylum, which is characterized by a soft body, often with a hard shell. Sea cucumbers are part of the Echinodermata phylum, known for their unique radial symmetry and water vascular system. Corals belong to the Cnidaria phylum and are characterized by their aquatic nature and the presence of stinging cells called cnidocytes. Each of these groups displays traits distinct from those found in Annelida, highlighting the unique biological characteristics of earthworms as a prime example of this phylum.