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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Q221.
Assertion (A): Aschelminthes are called roundworms.
Reason (R): The body of aschelminthes is circular in cross-section.
[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 common name "roundworms" for Aschelminthes is due to their body being circular in cross-section.
Q222.
Assertion (A): In Ascaris, the female is longer than the male.
Reason (R): Aschelminthes are dioecious, meaning sexes are separate.
[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. Females are often longer than males in Ascaris, and the phylum is dioecious. However, being dioecious (having separate sexes) does not by itself explain why one sex is larger than the other.
Q223.
Assertion (A): Annelids possess longitudinal and circular muscles.
Reason (R): These muscles 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: Annelids have both types of muscles, which work together to produce movement, thus aiding in locomotion.
Q224.
Assertion (A): Aquatic annelids like Nereis possess parapodia.
Reason (R): Parapodia are lateral appendages that help in swimming.
[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 lateral appendages found in aquatic annelids like Nereis are called parapodia, and their function is to assist in swimming.
Q225.
Assertion (A): Arthropoda is the largest phylum of Animalia.
Reason (R): Over two-thirds of all named species on earth are arthropods.
[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: Arthropoda is the largest phylum because it contains over two-thirds of all named animal species.
Q226.
Assertion (A): The body of arthropods is covered by a calcareous shell.
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: D [ ]
Remark: Assertion (A) is false but R is true. Explanation: Assertion is false; the body of arthropods is covered by a chitinous exoskeleton, not a calcareous shell (which is typical of molluscs). The reason is true; arthropods are characterized by jointed appendages.
Q227.
Assertion (A): Excretion in arthropods takes place through Malpighian tubules.
Reason (R): Arthropods have an open 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: Both statements are true facts about arthropods. However, the type of circulatory system is not the reason for having Malpighian tubules as excretory organs.
Q228.
Assertion (A): Mollusca is the second largest animal phylum.
Reason (R): The body of a mollusc is unsegmented and covered by a calcareous shell.
[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 correct descriptions of molluscs. However, the body characteristics mentioned in the reason do not explain why it is the second largest phylum.
Q229.
Assertion (A): The mouth of molluscs contains a radula.
Reason (R): The radula is a file-like rasping organ used for feeding.
[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 radula is the specific name for the file-like rasping organ in the mouth of molluscs, and its function is feeding.
Q230.
Assertion (A): The name Echinodermata means "spiny bodied".
Reason (R): These animals have an endoskeleton of calcareous ossicles.
[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 name Echinodermata directly translates to "spiny bodied," which refers to the endoskeleton of calcareous ossicles that gives them this appearance.
