Dentist specialties are recognized in those areas where advanced knowledge and skills are essential to maintain or restore oral health. The list of recognized dental specialties differs from country to country.
In contrast, radially symmetrical animals like jellyfish have a topside and a downside, but no identifiable front or back. The bilateria are a major group of animals, including the majority of phyla but not sponges, cnidarians, placozoans and ctenophores. For the most part, bilateral embryos are triploblastic, having three germ layers: endoderm, mesoderm, and ectoderm.
Another common type of symmetry is radial symmetry, in which an organism can be divided equally about a central point, much like a pie cut into equal parts.xamples. In the plant kingdom, it is common to see radial symmetry in flowers, though the rest of the plant may exhibit other symmetry, or no symmetry at all. Flower petals tend to extend from the central axis into a radial pattern, and fruits frequently have radial symmetry.