Symmetry in biology Most radially symmetric animals are symmetrical about an axis extending from the center of the oral surface, which contains the mouth to the center of the opposite, , end. Radial symmetry is especially suitable for sessile animals such as the sea anemone, floating animals such as jellyfish, and slow moving organisms such as starfish. Animals in the phyla Cnidaria and Echinodermata are radially symmetric, although many sea anemones and some corals have bilateral symmetry defined by a single structure, the siphonoglyph. Many flowers are radially symmetric or actinomorphic. Roughly identical flower parts – petals, sepals, and stamens – occur at
Lattice of subgroups finite lattice is isomorphic to a sublattice of the subgroup lattice of some finite group . Subgroups with certain properties form lattices, but other properties do not. However, neither finite subgroups nor torsion subgroups form a lattice: for instance, the free product formula_3 is generated by two torsion elements, but is infinite and contains elements of infinite order. The fact that normal subgroups form a modular lattice is a particular case of a more general result, namely that in any Maltsev variety (of which groups are an example), the lattice of congruences is modular . Lattice theoretic information about the