Phylum Mollusca MCQs January 8, 2026September 28, 2024 by u930973931_answers 30 min Score: 0 Attempted: 0/30 Subscribe 1. Mollusca is a phylum that includes which of the following organisms? (A) Snails and clams (B) Worms (C) Insects (D) Fish 2. The soft body of mollusks is typically divided into how many main parts? (A) Two (B) Five (C) Four (D) Three 3. Which structure is unique to mollusks and used for feeding? (A) Radula (B) Tentacle (C) Siphon (D) Gills 4. Mollusks are primarily classified into how many major classes? (A) Two (B) Four (C) Three (D) Eight 5. Which class of mollusks includes the octopus and squid? (A) Bivalvia (B) Gastropoda (C) Polyplacophora (D) Cephalopoda 6. Bivalves are characterized by having: (A) Two shells (B) No shell (C) A single shell (D) A segmented body 7. Which of the following is NOT a characteristic of mollusks? (A) Coelomate body plan (B) Segmented body (C) Presence of a mantle (D) Possession of a foot 8. What is the primary function of the mantle in mollusks? (A) Locomotion (B) Protection and shell secretion (C) Respiration (D) Digestion 9. The largest class of mollusks is: (A) Gastropoda (B) Bivalvia (C) Cephalopoda (D) Polyplacophora 10. Which of the following mollusks is known for its ability to change color? (A) Clam (B) Snail (C) Octopus (D) Oyster 11. How do most bivalves obtain their food? (A) Filter feeding (B) Hunting (C) Grazing (D) Parasitism 12. The siphon in mollusks is primarily used for: (A) Locomotion (B) Excretion (C) Reproduction (D) Respiration and feeding 13. Which mollusk is commonly known for its spiral shell? (A) Squid (B) Clam (C) Nautilus (D) Octopus 14. Mollusks reproduce primarily through: (A) Sexual reproduction (B) Asexual reproduction (C) Budding (D) Fragmentation 15. Which of the following is a characteristic of cephalopods? (A) They are typically sessile (B) They possess a foot used for burrowing (C) They have a reduced or absent shell (D) They have gills for respiration 16. Which mollusk is known for producing pearls? (A) Snail (B) Oyster (C) Squid (D) Cuttlefish 17. The foot of a mollusk is primarily used for: (A) Feeding (B) Reproduction (C) Respiration (D) Locomotion 18. What type of circulatory system do most mollusks have? (A) Closed circulatory system (B) Open circulatory system (C) Simple diffusion (D) Hemolymph system 19. Which class of mollusks includes organisms with a shell divided into eight plates? (A) Polyplacophora (B) Bivalvia (C) Gastropoda (D) Cephalopoda 20. Which of the following statements is true about gastropods? (A) They have two shells (B) They are exclusively marine (C) They lack a foot (D) They exhibit torsion during development 21. Which of the following mollusks is known for its advanced nervous system? (A) Clam (B) Chiton (C) Snail (D) Squid 22. What type of habitat do most mollusks occupy? (A) Terrestrial (B) Both terrestrial and aquatic (C) Aquatic (D) Only marine 23. Mollusks have a unique excretory structure called: (A) Mantle (B) Kidneys (C) Gills (D) Nephridia 24. The main component of a mollusk’s shell is: (A) Calcium carbonate (B) Chitin (C) Keratin (D) Silica 25. Mollusks are known to exhibit a variety of: (A) Body plans (B) Respiratory systems (C) All of the above (D) Feeding strategies 26. Which of the following is a common characteristic of all mollusks? (A) Presence of segmented body (B) Mantle and shell (C) Presence of antennae (D) Ability to fly 27. The term “torsion” in gastropods refers to: (A) The coiling of the shell (B) The method of locomotion (C) The process of feeding (D) The twisting of the body during development 28. What type of diet do most carnivorous mollusks have? (A) Predatory (B) Detritivorous (C) Planktivorous (D) Herbivorous 29. Which of the following structures is used by mollusks for respiration? (A) Gills (B) Lungs (C) Skin (D) Mantle 30. The primary ecological role of mollusks is: (A) Primary producers (B) Decomposers (C) Herbivores and predators (D) None of the above