[Campbell Biology P.750] Which of the following statements correctly differentiates between ... | Practice Question

Which of the following statements correctly differentiates between the mollusc groups discussed in the text?

  • A: Unlike gastropods and cephalopods, bivalves typically lack a distinct head and radula.
  • B: All cephalopods possess a prominent external shell, similar to many gastropods.
  • C: Terrestrial snails (gastropods) primarily use gills for gas exchange, just like aquatic bivalves.
  • D: Bivalves are active marine predators that use tentacles to grasp prey.

Explanation

The text explicitly states for bivalves: 'Bivalves have no distinct head, and the radula has been lost.' In contrast, gastropods typically have a head and radula, and cephalopods, while their 'foot' is modified, also have distinct head features and beak-like jaws a different feeding structure from a radula .