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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Q241.
Assertion (A): Chondrichthyes have a cartilaginous endoskeleton.
Reason (R): Their notochord is persistent throughout life.
[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 features of Chondrichthyes. However, the persistence of the notochord is a separate primitive trait and not the reason for the endoskeleton being cartilaginous.
Q242.
Assertion (A): Sharks must swim constantly to avoid sinking.
Reason (R): They lack an air bladder.
[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 air bladder provides buoyancy in bony fish. Since sharks lack this organ, they must keep swimming to generate lift and prevent sinking.
Q243.
Assertion (A): The teeth of sharks are modified placoid scales.
Reason (R): The skin of Chondrichthyes is tough and contains minute placoid scales.
[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 teeth in sharks are structurally homologous to the placoid scales covering their skin; they are essentially modified, enlarged placoid scales.
Q244.
Assertion (A): Some cartilaginous fish like Torpedo have electric organs.
Reason (R): Chondrichthyes are warm-blooded (homoiothermous) animals.
[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: Some cartilaginous fishes (e.g., Torpedo) have electric organs (true). The reason is false; Chondrichthyes are poikilothermous (cold-blooded).
Q245.
Assertion (A): Osteichthyes includes fishes with a bony endoskeleton.
Reason (R): They possess an air bladder which regulates buoyancy.
[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 features of Osteichthyes. The presence of an air bladder is an important feature, but it doesn't explain why their skeleton is bony.
Q246.
Assertion (A): In bony fishes, gills are covered by an operculum.
Reason (R): In cartilaginous fishes, gill slits are separate and without an operculum.
[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 descriptions of bony and cartilaginous fishes, respectively. They are contrasting features but one does not explain the other.
Q247.
Assertion (A): Amphibians can live in both aquatic and terrestrial habitats.
Reason (R): The name Amphibia indicates a dual life.
[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 Amphibia (Amphi: dual, bios: life) literally means 'dual life,' referring to their ability to inhabit both aquatic and terrestrial environments.
Q248.
Assertion (A): Amphibians have a three-chambered heart.
Reason (R): Their heart has two auricles and one ventricle.
[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 amphibian heart is described as three-chambered because it is composed of two auricles and one ventricle.
Q249.
Assertion (A): The skin of amphibians is moist and without scales.
Reason (R): Respiration in amphibians can occur through gills, lungs, and skin.
[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 features of amphibians. The moist, scaleless skin facilitates cutaneous (skin) respiration, but the reason also lists other modes (gills, lungs), making it a related but not a direct explanation.
Q250.
Assertion (A): In amphibians, the alimentary, urinary, and reproductive tracts open into a common cloaca.
Reason (R): Fertilisation in amphibians is internal and development is direct.
[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: Assertion is correct. The reason is false; fertilisation in amphibians is typically external, and development is indirect (involving a larval stage).
