Symmetry in biology is the balanced distribution of duplicate body parts or shapes within the body of an organism. In nature and biology,
symmetry is always approximate: for example plant leaves, while considered symmetrical, rarely match up exactly when folded in half. Symmetry creates a class of
patterns in nature, where the near-repetition of the pattern element is by
reflection or
rotation. The
body plans of most
multicellular organisms exhibit some form of symmetry, whether radial, bilateral, or spherical. A small minority, notably among the
sponges, exhibit no symmetry (i.e., are asymmetric).