What is the body symmetry of annelids?

What is the body symmetry of annelids?

• A. Bilateral
• B. Radial
• C. Asymmetrical
• D. Spherical

Answer: (A)

Annelids have bilateral symmetry, meaning their body has a left and a right side that are mirror images along a single plane from head to tail. This setup supports directional movement and cephalization, where sensory and feeding structures cluster at the anterior end. The segmented, elongated form of annelids fits this symmetry and helps coordinate movement along a defined front-to-back axis. In contrast, radial symmetry would give multiple planes of symmetry around a central axis (seen in jellyfish or starfish), asymmetry would lack any symmetric plan (as in some sponges), and spherical symmetry would have equal halves in any cut through the center—none of which describe annelids.

Annelids have bilateral symmetry, meaning their body has a left and a right side that are mirror images along a single plane from head to tail. This setup supports directional movement and cephalization, where sensory and feeding structures cluster at the anterior end. The segmented, elongated form of annelids fits this symmetry and helps coordinate movement along a defined front-to-back axis. In contrast, radial symmetry would give multiple planes of symmetry around a central axis (seen in jellyfish or starfish), asymmetry would lack any symmetric plan (as in some sponges), and spherical symmetry would have equal halves in any cut through the center—none of which describe annelids.