GENERAL HISTOLOGY

Detailed explanation-1: -All adult forms of modern echinoderms have 5-point, or pentaradial symmetry, meaning that they have morphological features that are divisible by five.

Detailed explanation-2: -Echinoderms (starfish, sea urchins and their allies) are an exception; all modern species exhibit pentaradial (five-fold) symmetry, but the phylum also possesses an extensive fossil record that includes bilateral, asymmetrical and radial forms [1, 2].

Detailed explanation-3: -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-4: -In the animal kingdom, there is only one known phylum that exhibits pentaradial symmetry, and that’s the Phylum Echinodermata. Echinoderms include sea stars (or starfish), sea urchins, sea lilies, sand dollars, and sea cucumbers.

Detailed explanation-5: -Echinoderms are invertebrates that have pentaradial symmetry, a spiny skin, a water vascular system, and a simple nervous system.