Practice question

Cnidaria and Ctenophora exhibit predominantly radial symmetry where multiple longitudinal planes through central oral-aboral axis divide body into mirror halves, an adaptation advantageous for sessile polyps or drifting medusae capturing prey arriving from all directions using circumoral tentacles bearing cnidocytes or colloblasts. Some ctenophores show biradial symmetry due to paired tentacles and pharynx. Bilateral symmetry with single sagittal plane characterizes Bilateria enabling directed locomotion and cephalization, while asymmetrical or spherical symmetries seen in irregular sponges or Volvox not applicable to cnidarians.