Practice MCQs, Assertion–Reason, Match List and Fill in the Blanks from NCERT Class XI Animal Kingdom — answers & concise explanations.
Animal Kingdom - Class-XI: Practice ( MCQs, Assertion-Reason, Match List-I with List-II and Fill in the Blanks) for CBSE and NEET preparation 2026.
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Q261.
Assertion (A): Phylum Ctenophora reproduces only by sexual means.
Reason (R): In ctenophores, sexes are not separate, and fertilisation is external.
[Animal-Kingdom] [class-xi]
a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
c) Assertion (A) is true but Reason (R) is false.
d) Assertion (A) is false but Reason (R) is true.
Correct Option: A [ ]
Remark: Both A and R are true and R is the correct explanation of A. Explanation: Many ctenophores reproduce sexually; sexes are not always separate (some are hermaphrodite) and fertilisation is typically external.
Q262.
Assertion (A): Some members of Platyhelminthes like Planaria possess high regeneration capacity.
Reason (R): They are exclusively endoparasites.
[Animal-Kingdom] [class-xi]
a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
c) Assertion (A) is true but Reason (R) is false.
d) Assertion (A) is false but Reason (R) is true.
Correct Option: C [ ]
Remark: A is true but R is false. Explanation: Planaria have remarkable regenerative ability and are free-living (not exclusively endoparasites).
Q263.
Assertion (A): A closed circulatory system is present in Annelida.
Reason (R): Blood is circulated through a series of vessels of varying diameters.
[Animal-Kingdom] [class-xi]
a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
c) Assertion (A) is true but Reason (R) is false.
d) Assertion (A) is false but Reason (R) is true.
Correct Option: A [ ]
Remark: Both A and R are true and R is the correct explanation of A. Explanation: Annelids have a closed circulatory system where blood flows through vessels.
Q264.
Assertion (A): Limulus (King crab) is called a living fossil.
Reason (R): It is a gregarious pest.
[Animal-Kingdom] [class-xi]
a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
c) Assertion (A) is true but Reason (R) is false.
d) Assertion (A) is false but Reason (R) is true.
Correct Option: C [ ]
Remark: A is true but R is false. Explanation: Limulus (horseshoe crab) is called a living fossil due to its ancient lineage; the reason claiming it is a gregarious pest is incorrect.
Q265.
Assertion (A): The body of a mollusc is unsegmented.
Reason (R): The body of an annelid shows metameric segmentation.
[Animal-Kingdom] [class-xi]
a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
c) Assertion (A) is true but Reason (R) is false.
d) Assertion (A) is false but Reason (R) is true.
Correct Option: A [ ]
Remark: Both A and R are true and R is the correct explanation of A. Explanation: Molluscs are generally unsegmented; annelids show clear metamerism — contrasting features.
Q266.
Assertion (A): The excretory organ in Hemichordata is the proboscis gland.
Reason (R): Hemichordates have an open type circulatory system.
[Animal-Kingdom] [class-xi]
a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
c) Assertion (A) is true but Reason (R) is false.
d) Assertion (A) is false but Reason (R) is true.
Correct Option: B [ ]
Remark: Both A and R are true but R is not the correct explanation of A. Explanation: The statements are facts about hemichordates; the circulatory type does not explain the excretory organ identity.
Q267.
Assertion (A): In chordates, the heart is ventral.
Reason (R): In non-chordates, the heart, if present, is dorsal.
[Animal-Kingdom] [class-xi]
a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
c) Assertion (A) is true but Reason (R) is false.
d) Assertion (A) is false but Reason (R) is true.
Correct Option: A [ ]
Remark: Both A and R are true and R is the correct explanation of A. Explanation: A ventral heart is typical of chordates, contrasting with dorsal hearts of many non-chordates.
Q268.
Assertion (A): Gnathostomata is a division of vertebrates that bears jaws.
Reason (R): Gnathostomata includes superclasses Pisces and Tetrapoda.
[Animal-Kingdom] [class-xi]
a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
c) Assertion (A) is true but Reason (R) is false.
d) Assertion (A) is false but Reason (R) is true.
Correct Option: A [ ]
Remark: Both A and R are true and R is the correct explanation of A. Explanation: Gnathostomata comprises jawed vertebrates including fishes (pisces) and tetrapods.
Q269.
Assertion (A): Members of Chondrichthyes are viviparous.
Reason (R): Males possess claspers on their pelvic fins for internal fertilisation.
[Animal-Kingdom] [class-xi]
a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
c) Assertion (A) is true but Reason (R) is false.
d) Assertion (A) is false but Reason (R) is true.
Correct Option: B [ ]
Remark: Both A and R are true but R is not the correct explanation of A. Explanation: Some chondrichthyans are viviparous and males use claspers; however the presence of claspers facilitates internal fertilisation but does not mean all members are viviparous.
Q270.
Assertion (A): Osteichthyes are mostly oviparous.
Reason (R): Fertilisation in bony fishes is usually external.
[Animal-Kingdom] [class-xi]
a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
c) Assertion (A) is true but Reason (R) is false.
d) Assertion (A) is false but Reason (R) is true.
Correct Option: A [ ]
Remark: Both A and R are true and R is the correct explanation of A. Explanation: Most bony fishes lay eggs and external fertilisation is common, explaining oviparity.
