Radial Symmetry

Radial Symmetry (Starfish)

"Symmetry, in biology, is the repetition of the parts in an animal or plant in an orderly fashion". More specifically, it's the way those repetitions correspond to each other on opposite sides of a dividing line. In radial symmetry, those corresponding parts radiate from a central axis and are arranged in regular fashion. The main axis is called the "oral-aboral", because the anterior side bears the mouth and the posterior end may bear the anus. The starfish can be labeled as a five-rayed animal because of its five symmetrical parts.