In biology, homogeneity is the distribution of imitation body parts or shapes within an organism. Symmetry in nature and biology is always approximate. For example , the leaves of plants - considered symmetrical - rarely match when folded in half. Symmetry forms a pattern of nature , where the pattern is repeated by reflection or rotation around the element . A small minority , especially among sponges , show no symmetry (i.e. , asymmetric). At one time the symmetry of animal synthesis was important ; Radiatata , an animal with radial symmetry , formed one of the four branches of Georges Cuvier's animal kingdom taxonomy.