Question

Animal with unsegmented, coelomates and radially symmetrical body having distinct oral and aboral surfaces belong to
A) Annelida
B) Mollusca
C) Echinodermata
D) Porifera
E) Arthropoda

Answer 1

Hint: In the biology there is a level of classification where phylum is one among it, and that is present below the kingdom and above the class, previously it was named as division which is based on the international code of nomenclature for the algae, and fungi and plants that accepts the terms of all as equivalence.

Complete answer:
The organisms which are given in the above options are segmented in their body and some are unsegmented, and some are coelomates but some are acoelomates, but the oral and abroad surfaces among above given options are present only in Echinoderms.
A) Annelids have segmented body and are coelomate and have bilaterally symmetrical
B) Molluscs have unsegmented bodies which are coelomate and are asymmetrical.
C) Echinoderms are unsegmented body coelomate, and larva has bilateral symmetry and adults possess radially symmetrical and have distinct oral and abdominal surfaces.
D) Poriferans bodies are unsegmented, acoelomate and most of them are asymmetrical.
When coming to Arthropods their bodies are segmented, coelomate and possess bilateral symmetry.
E) The common name for the animals of Echinodermata are called Echinoderms, where most of them are marine animals, and Echinoderm evolved 2 types of symmetry in their lifetime.
They are larval stages of echinoderms possessing bilateral symmetry which derived from the previous animals, and the adult forms possess pentaradial or five sided symmetry.
The larvae of the Echinoderms are ciliated and free swimming with bilateral symmetry may appear as embryonic chordata.
When this larva is growing the left part of the body grows at an expense of the right side, where the right side is absorbed eventually.
They have mesodermal skeleton and also they have calcareous plates and skeletal elements which are deployed in some specialized ways such as Aristotle lanterns.

So, the correct option is C.

Note: This Echinodermata possesses a unique vascular system and their coelomates where some networks of fluid filled canals are derived from the coelom, and this fluid has some cells called Coelomocytes that simply act as immune cells.