Questions on Mollusks (Phylum Mollusca)
Mollusks – Multiple Choice Questions
1. Mollusks are members of which animal phylum?
A) Annelida
B) Arthropoda
C) Mollusca
D) Nematoda
E) Porifera
2. Which of the following is a characteristic feature of all mollusks?
A) Jointed appendages
B) Radial symmetry
C) Exoskeleton made of chitin
D) Soft body, often with a shell
E) Segmented body
3. What is the function of the mantle in mollusks?
A) Respiration
B) Circulation
C) Producing the shell
D) Digestion
E) Movement
4. Which mollusk class includes snails and slugs?
A) Bivalvia
B) Cephalopoda
C) Gastropoda
D) Polyplacophora
E) Scaphopoda
5. Which class of mollusks includes clams, oysters, and mussels?
A) Gastropoda
B) Cephalopoda
C) Polyplacophora
D) Bivalvia
E) Monoplacophora
6. Cephalopods are known for their:
A) Slow movement and thick shells
B) Jointed legs
C) Complex eyes and high intelligence
D) Filter feeding
E) Absence of tentacles
7. The radula in mollusks is used for:
A) Reproduction
B) Circulation
C) Feeding
D) Respiration
E) Locomotion
8. Which mollusk does not have a shell?
A) Mussel
B) Octopus
C) Snail
D) Scallop
E) Nautilus
9. Mollusks have what type of body symmetry?
A) Asymmetrical
B) Radial
C) Bilateral
D) Spherical
E) Spiral
10. What kind of circulatory system do cephalopods possess?
A) None
B) Open circulatory system
C) Closed circulatory system
D) Diffused through body wall
E) Shared with digestive system
11. Mollusks typically have how many main body parts?
A) 2
B) 3
C) 4
D) 5
E) 6
12. Which body region contains most of the internal organs of a mollusk?
A) Head
B) Mantle
C) Shell
D) Visceral mass
E) Foot
13. Which of the following mollusks is a cephalopod?
A) Clam
B) Slug
C) Scallop
D) Squid
E) Chiton
14. The shell of a mollusk is primarily made of:
A) Cellulose
B) Silica
C) Keratin
D) Calcium carbonate
E) Chitin
15. Which mollusk is a filter feeder?
A) Snail
B) Squid
C) Clam
D) Octopus
E) Slug
16. What is the primary role of the foot in most mollusks?
A) Respiration
B) Feeding
C) Movement
D) Circulation
E) Shell formation
17. Mollusks are:
A) Acoelomates
B) Pseudocoelomates
C) Coelomates
D) Diploblastic
E) Prokaryotic
18. Which class of mollusks is considered the most intelligent?
A) Gastropoda
B) Bivalvia
C) Cephalopoda
D) Polyplacophora
E) Monoplacophora
19. Which of the following mollusks has tentacles with suckers?
A) Snail
B) Clam
C) Octopus
D) Chiton
E) Mussel
20. Which structure helps aquatic mollusks with gas exchange?
A) Gills
B) Mantle cavity
C) Foot
D) Radula
E) Shell
Answers with Explanations
1. C) Mollusca – Mollusks belong to the phylum Mollusca.
2. D) Soft body, often with a shell – All mollusks have a soft body; many have shells.
3. C) Producing the shell – The mantle secretes calcium carbonate to form the shell.
4. C) Gastropoda – Snails and slugs are gastropods.
5. D) Bivalvia – Clams, oysters, and mussels are bivalves with two shells.
6. C) Complex eyes and high intelligence – Cephalopods like octopuses are highly intelligent.
7. C) Feeding – The radula is a tongue-like organ used to scrape or cut food.
8. B) Octopus – Octopuses lack external shells.
9. C) Bilateral – Mollusks are bilaterally symmetrical.
10. C) Closed circulatory system – Cephalopods are the only mollusks with a closed system.
11. B) 3 – Head, foot, and visceral mass are the three main parts.
12. D) Visceral mass – Contains organs like heart, digestive, excretory, and reproductive systems.
13. D) Squid – Squid is a member of the class Cephalopoda.
14. D) Calcium carbonate – Mollusk shells are made of this mineral.
15. C) Clam – Clams filter food from water using gills.
16. C) Movement – The foot is typically used for locomotion.
17. C) Coelomates – Mollusks have a true body cavity.
18. C) Cephalopoda – Octopuses and squids show high intelligence.
19. C) Octopus – Octopuses have tentacles with suckers.
20. A) Gills – Used in aquatic respiration.
Practical Classroom Applications
- Compare mollusks with annelids and arthropods in invertebrate classification lessons.
- Explore marine and freshwater adaptations in different mollusk groups.
- Discuss evolutionary biology using cephalopods, gastropods, and bivalves as examples.
- Apply biodiversity concepts in environmental science activities.
- Use anatomy and reproduction questions to reinforce zoology vocabulary.
- Create classroom discussions about aquatic ecosystems and conservation.
- Develop critical thinking through taxonomy and adaptation exercises.
- Use the material for biology reviews, STEM projects, and assessments.
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