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.
Radial symmetry means (biologically) that the animal structures are situated in a radial or circular pattern around a center point with nonexistence of sides, like right or left.~ describes an organ ism that can be divided in any longitudinal plane to give two approximately identical halves.haracter izing a body shaped like a pie or barrel, with many equal parts radiating outward like the spokes of a wheel; present in cnidarians and echinoderms. radiation ... radial symmetry.