Question

Body cavity of Annelida/Nereis is
(a) Schizocoel
(b) Enterocoel
(c) Pseudocoel
(d) None of the above

Answer 1

Hint: Phylum Annelida is a large phylum. Annelids are mostly known as ringworms or segmented worms. They are coelomate (body cavity) and triploblastic.

Complete answer:
Annelids that develop through schizocoely are known as schizocoelomates animals. A process by which some animal embryos develop is termed as Schizocoely. Schizocoely occurs when a coelom (body cavity) is formed by splitting the mesodermal embryonic tissue (Schizocoel).
Schizocoel is divided by transverse septa into the compartment. It is filled with coelomic fluid that contains cells. As such, there is no skeleton, Fluid-filled coelom serves as a hydrostatic skeleton.
Nearly all annelids possess fluid-filled cavities. The coelom is referred to as the space between the outer body wall and the gut. The coelom is usually used as a storage of gametes and acts as a hydrostatic skeleton for locomotion. The coelom (formed via schizocoely) is usually organized as a series of compartments by intersegment septa.

So, the correct answer is ‘Schizocoel’.

Note: The body of Nereis dumerilii is a transverse section that looks like a tube within a tube. The wall of the outer large tube is the body wall and the wall of the inner small tube is the gut wall. In between the two walls, lies a spacious cavity called a coelom or body cavity, which is filled up with fluid.