Q41. The phylum Arthropoda includes organisms that often possess an exoskeleton made primarily of:
a) Calcium carbonate
b) Silica
c) Chitin
d) Cellulose
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Correct Answer: c) Chitin
Explanation: Arthropods, such as insects, spiders, crustaceans, and centipedes, possess an exoskeleton made primarily of chitin, a tough polysaccharide. This exoskeleton provides protection and support for the organism.
Q42. Members of the phylum
Q42. Members of the phylum Mollusca commonly exhibit which type of feeding strategy?
a) Filter feeding
b) Predation
c) Herbivory
d) Parasitism
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Correct Answer: a) Filter feeding
Explanation: Many mollusks, such as clams and mussels, are filter feeders. They use structures like gills or ciliated surfaces to capture plankton and other small particles suspended in water.
Q43. The phylum Cnidaria includes organisms that possess a simple, sac-like body plan with a central digestive cavity called a:
a) Coelom
b) Radula
c) Nematocyst
d) Gastrovascular cavity
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Correct Answer: d) Gastrovascular cavity
Explanation: Cnidarians, such as jellyfish and sea anemones, have a gastrovascular cavity that serves both as a digestive chamber and a circulatory system. It has a single opening serving as both mouth and anus.
Q44. Organisms belonging to the phylum Annelida are typically characterized by which type of symmetry?
a) Bilateral symmetry
b) Radial symmetry
c) Asymmetry
d) Pentaradial symmetry
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Correct Answer: a) Bilateral symmetry
Explanation: Annelids, such as earthworms and leeches, exhibit bilateral symmetry, meaning their bodies can be divided into two mirror-image halves along a central plane.
Q45. The phylum Echinodermata includes organisms with a unique water vascular system used primarily for:
a) Respiration
b) Digestion
c) Locomotion
d) Sensory perception
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Correct Answer: c) Locomotion
Explanation: Echinoderms, such as sea stars and sea urchins, possess a water vascular system, which functions in locomotion by the movement of water through a series of fluid-filled canals and tube feet.
Q46. Members of the phylum Nematoda are known for their diversity and abundance in which of the following environments?
a) Terrestrial
b) Marine
c) Freshwater
d) Desert
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Correct Answer: a) Terrestrial
Explanation: Nematodes, or roundworms, are found in a wide range of terrestrial habitats, including soil, leaf litter, and decomposing organic matter. They play essential roles in nutrient cycling and ecosystem functioning.
Q47. The phylum Platyhelminthes includes organisms that are often characterized by which type of body plan?
a) Cylindrical with bilateral symmetry
b) Flattened with radial symmetry
c) Segmented with pentaradial symmetry
d) Spherical with asymmetry
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Correct Answer: a) Cylindrical with bilateral symmetry
Explanation: Platyhelminths, or flatworms, typically have a flattened, ribbon-like body shape with bilateral symmetry. This body plan allows them to move effectively in their aquatic or moist environments.
Q48. Organisms belonging to the phylum Chordata are characterized by the presence of which of the following structures at some stage of their development?
a) Exoskeleton
b) Radula
c) Notochord
d) Cnidocytes
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Correct Answer: c) Notochord
Explanation: Chordates have a notochord, a flexible rod-like structure that provides support and serves as a primitive backbone in vertebrates. It is present at some stage of their development, distinguishing them from other phyla.
Q49. The phylum Arthropoda is the largest phylum in the animal kingdom, comprising approximately what percentage of all known animal species?
a) Less than 10%
b) Approximately 25%
c) Around 50%
d) More than 75%
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Correct Answer: d) More than 75%
Explanation: Arthropods make up the largest and most diverse phylum in the animal kingdom, comprising over 75% of all known animal species. They exhibit remarkable adaptations and inhabit virtually every habitat on Earth.
Q50. Which of the following phyla includes organisms that exhibit a high degree of cephalization and often possess a well-developed brain and sensory organs?
a) Porifera
b) Cnidaria
c) Platyhelminthes
d) Chordata
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Correct Answer: d) Chordata
Explanation: Chordates, including vertebrates, exhibit a high degree of cephalization, with a concentration of sensory organs and nervous tissue in the head region. This adaptation is associated with improved sensory perception and coordination.