GENERAL HISTOLOGY

Detailed explanation-1: -Pentaradial symmetry is a type of radial symmetry, which is a characteristic of echinoderms, in which body parts are arranged along five rays of symmetry. It means the organism is in five parts around a central axis.

Detailed explanation-2: -Echinoderms are a phylum exclusively consisting of marine animals. The adults are recognizable by their radial symmetry whereas their larvae are bilaterally symmetrical.

Detailed explanation-3: -Although very diverse in body form, all echinoderms possess the typical pentaradial symmetry of the phylum and their limbs and organs generally exist in multiples of five. As adults, echinoderms usually lack an anterior head region.

Detailed explanation-4: -Pentaradial symmetry is easily observed in echinoderms such as sea stars and sand dollars, which both have externally visible divisions of their body segments into five equal parts. However, other types of echinoderms, like sea urchins and sea cucumbers lack these external markers of pentaradial symmetry.

Detailed explanation-5: -One characteristic of an echinoderm is that they all have pentamerous radial symmetry. This simply means they all have 5 equal body parts. You can divide these animals into five equal parts, and every part is the same. For example, most sea stars have five arms or a multiple of five arms.