Zoology 10th Edition by Stephen Miller,John Harley

Exercise 8

The body of a mollusc is divided into two regions. The head-foot contains the mouth, nervous structures, and a muscular foot used in attachment and locomotion. The visceral mass contains organs of digestion, reproduction, and excretion. Distinctive molluscan structures also include the mantle, mantle cavity, and the radula.
Which of the molluscan characteristics listed at the beginning of this section are unique to the molluscs?