Question

The figure shows four animals (a), (b), (c) and (d). Select the correct answer with respect to common characteristics of two of these animals.

• A. (a) and (d) respire mainly through body wall.
• B. (b) and (c) show radial symmetry.
• C. (a) and (b) have cnidoblasts for self-defense.
• D. (c) and (d) have a true coelom.

Answer 1

The correct option is D (c) and (d) have a true coelom.

All complex animals have a true coelom, including the molluscs, annelids, arthropods, echinoderms and chordates. They have a true coelom, that is completely lined by the mesoderm layer. An octopus is a cephalopod mollusc of the order Octopoda. Octopuses are among the most intelligent and behaviorally flexible of all invertebrates. All the advanced invertebrate phyla have a true coelom. In mollusks, annelids, and arthropods, the coelom forms by splitting of the mesoderm. Therefore, they are called the schizocoelomates. Scorpions are predatory arthropod animals of the order Scorpiones within the class Arachnida. In echinoderms and chordates, the coelom forms by outpocketing of the primitive gut. It is thus, called enterocoelomates.Thus the correct option is D.