Answer:
Characteristics:
They are bilaterally symmetrical. They are triploblastic, which three layers. They show organ system grade of organisation. The body is soft and unsegmented. Body is divisible into three regions – head, a visceral mass, and ventral foot. Body is covered by a mantle and shell. Mollusks interact with eachother differently. The deliberate production of sound is used to attract mates, ward of predators, locate prey, and in social communication. Of course there needs to be recipients to hear and interpret the sound. ... Sound and vibration detection is known also in molluscs. On the tentacles of gastropods sensory cells can detect vibration.