Q11. Which of the following phyla includes animals with a segmented body and a water vascular system?
a) Mollusca
b) Echinodermata
c) Annelida
d) Hemichordata
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Correct Answer: b) Echinodermata
Explanation: Echinoderms possess a unique water vascular system, which is a network of fluid-filled canals used for locomotion, feeding, and gas exchange. This system is characteristic of echinoderms like sea stars and sea urchins.
Q12. Organisms belonging to the phylum Porifera primarily feed through:
a) Filter feeding
b) Predation
c) Herbivory
d) Parasitism
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Correct Answer: a) Filter feeding
Explanation: Poriferans, or sponges, primarily feed through filter feeding. They draw in water through pores in their bodies and filter out small particles of organic matter for food while expelling excess water.
Q13. Which of the following is a characteristic feature of organisms in the phylum Cnidaria?
a) Segmentation
b) Radial symmetry
c) Jointed appendages
d) Exoskeleton
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Correct Answer: b) Radial symmetry
Explanation: Cnidarians exhibit radial symmetry, meaning their body parts are arranged around a central axis. This symmetry allows them to capture prey from any direction and is typical of organisms like jellyfish and coral polyps.
Q14. Flatworms are characterized by:
a) Segmented bodies
b) Radial symmetry
c) Cilia for locomotion
d) Dorsoventrally flattened bodies
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Correct Answer: d) Dorsoventrally flattened bodies
Explanation: Flatworms, or Platyhelminthes, have flattened bodies with a distinct dorsal and ventral side. This morphology allows them to maximize surface area for gas exchange and diffusion of nutrients.
Q15. Which of the following phyla includes organisms with a pseudocoelom?
a) Porifera
b) Platyhelminthes
c) Annelida
d) Aschelminthes
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Correct Answer: d) Aschelminthes
Explanation: Aschelminthes, also known as roundworms or nematodes, possess a pseudocoelom, which is a fluid-filled body cavity located between the mesoderm and endoderm. This cavity provides space for internal organs but is not fully lined by mesoderm.
Q16. The presence of setae is a characteristic feature of organisms in which phylum?
a) Annelida
b) Mollusca
c) Arthropoda
d) Echinodermata
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Correct Answer: a) Annelida
Explanation: Annelids, such as earthworms and leeches, possess setae, which are bristle-like structures protruding from their body segments. Setae aid in locomotion and anchoring within the substrate.
Q17. Animals in the phylum Arthropoda undergo which type of metamorphosis?
a) Incomplete metamorphosis
b) Holometabolous metamorphosis
c) Hemimetabolous metamorphosis
d) Direct development
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Correct Answer: b) Holometabolous metamorphosis
Explanation: Arthropods undergo holometabolous metamorphosis, which involves distinct larval, pupal, and adult stages. Examples include butterflies, beetles, and flies.
Q18. A radula is a feeding structure characteristic of organisms in which phylum?
a) Mollusca
b) Echinodermata
c) Annelida
d) Hemichordata
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Correct Answer: a) Mollusca
Explanation: Mollusks possess a radula, which is a rasping, tongue-like structure covered with rows of tiny teeth. The radula is used for scraping and feeding on various food sources, such as algae and detritus.
Q19. The water vascular system is a unique feature of organisms in which phylum?
a) Mollusca
b) Echinodermata
c) Annelida
d) Arthropoda
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Correct Answer: b) Echinodermata
Explanation: Echinoderms possess a water vascular system, which is a network of fluid-filled canals used for locomotion, feeding, and gas exchange. This system is unique to echinoderms like sea stars and sea urchins.
Q20. The larval stage of many mollusks is called:
a) Trochophore
b) Nauplius
c) Planula
d) Tadpole
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Correct Answer: a) Trochophore
Explanation: The trochophore larva is a characteristic larval stage found in many mollusks and some other invertebrates. It is typically free-swimming and possesses a ciliated band for locomotion and feeding.