Solution

Hemichordates are bilaterally symmetrical; the other phyla are radially symmetrical as adults.

Radial symmetry: When any plane passing through the central axis of the body divides the organism into two identical halves. Bilateral symmetry: When the body can be divided into identical left and right halves in only one plane. The adult echinoderms are radially symmetrical but larvae are bilaterally symmetrical. Coelenterates and Ctenophores are radially symmetrical animals. Hemichordates are bilaterally symmetrical animals.

Concept radial vs bilateral symmetry

Animal Kingdom in past papers

123 questions from this chapter have appeared across 27 exam years.