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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Q211.
Assertion (A): Platyhelminthes are acoelomates.
Reason (R): The body cavity is absent in flatworms.
[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: Acoelomates lack a body cavity; Platyhelminthes (flatworms) are acoelomate.
Q212.
Assertion (A): The body of an earthworm shows metamerism.
Reason (R): The earthworm's body is externally and internally divided into segments with a serial repetition of some organs.
[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: Metamerism refers to segmentation with serial repetition of organs; earthworms exhibit this.
Q213.
Assertion (A): Animals with a notochord are called chordates.
Reason (R): The notochord is an ectodermally derived rod-like structure.
[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: Animals with a notochord are chordates (true). The notochord is mesodermally derived, not ectodermal, so the reason is false.
Q214.
Assertion (A): The water canal system in sponges is helpful in food gathering and respiratory exchange.
Reason (R): Water enters through the osculum and exits through minute pores called ostia.
[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: Sponges' water canal system aids feeding and respiration (true). Water actually enters via ostia (pores) and exits through the osculum — the reason had the flow reversed.
Q215.
Assertion (A): The name Cnidaria is derived from the presence of cnidoblasts.
Reason (R): Cnidoblasts are used for anchorage, defense, and capture of prey.
[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: Both statements are true: the phylum name refers to cnidoblasts, and cnidoblasts function in anchorage/defense/prey capture; but the function is not the reason for the etymology.
Q216.
Assertion (A): Some cnidarians like Obelia exhibit metagenesis.
Reason (R): In Obelia, polyps produce medusae sexually and medusae produce polyps asexually.
[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: Obelia shows metagenesis (true), but the reproduction modes are reversed in the reason: polyps produce medusae asexually and medusae produce polyps sexually.
Q217.
Assertion (A): Ctenophores are commonly known as comb jellies.
Reason (R): Their body bears eight external rows of ciliated comb plates which help in locomotion.
[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: Ctenophores are called comb jellies due to their eight rows of ciliated comb plates used for locomotion.
Q218.
Assertion (A): Bioluminescence is well-marked in ctenophores.
Reason (R): Bioluminescence is the property of a living organism to emit light.
[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: Bioluminescence is indeed common in ctenophores and the reason correctly defines bioluminescence, but that definition does not explain why it occurs in ctenophores specifically.
Q219.
Assertion (A): Platyhelminthes are called flatworms.
Reason (R): They have a dorso-ventrally flattened body.
[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: The term "flatworms" refers to their dorso-ventrally flattened body.
Q220.
Assertion (A): Parasitic flatworms possess hooks and suckers.
Reason (R): Flame cells in flatworms help in osmoregulation and excretion.
[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: Both statements are true features of parasitic flatworms. However, the presence of flame cells for excretion is a separate physiological feature and does not explain the presence of hooks and suckers for attachment.
