The Bilateral symmetry reference article from the English Wikipedia on 24-Jul-2004 (provided by Fixed Reference: snapshots of Wikipedia from wikipedia.org)

Bilateral symmetry

In biology, bilateral symmetry is a characteristic of multicellular organisms, particularly animals. A bilaterally symmetric organism is one that is symmetric about a plane running from its frontal end to its caudal end (head to tail), and has nearly identical right and left halves.

Most animals are bilaterally symmetric, including humans. The exceptions are sponges (no symmetry), jellyfish and ctenophores (radial symmetry), and echinoderms (partial radial symmetry).

See also: radial symmetry

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