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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Q391.
In adult vertebrates, the embryonic notochord is replaced by?
[Animal-Kingdom] [class-xi]
Nerve cord
Vertebral column
Rib cage
Sternum
Correct Option: B [ Vertebral column ]
Remark: During the development of vertebrates, the notochord is present in the embryonic stage but is replaced by a cartilaginous or bony vertebral column in the adult.
Q392.
Vertebrates are also known as Craniata because they possess a?
[Animal-Kingdom] [class-xi]
Backbone
Skull box
Jaw
Lung
Correct Option: B [ Skull box ]
Remark: The term Craniata refers to animals that possess a cranium or skull box that encloses and protects the brain. All vertebrates fall into this category.
Q393.
The Polyp body form is absent in which Cnidarian?
[Animal-Kingdom] [class-xi]
Hydra
Aurelia
Physalia
Obelia
Correct Option: B [ Aurelia ]
Remark: Aurelia, commonly known as the Jellyfish, primarily exists in the Medusa form. The sessile Polyp phase is reduced or absent in its life cycle.
Q394.
Hydra primarily exhibits which body form?
[Animal-Kingdom] [class-xi]
Medusa
Polyp
Larval
Flat
Correct Option: B [ Polyp ]
Remark: Hydra is a classic example of the Polyp body form in Cnidarians. It is cylindrical and sessile (attached to a substrate), unlike the free-swimming Medusa.
Q395.
Aurelia is commonly known by what name?
[Animal-Kingdom] [class-xi]
Portuguese man of war
Jelly fish
Sea Anemone
Coral
Correct Option: B [ Jelly fish ]
Remark: Aurelia is the scientific name for the common Jellyfish, which is a free-swimming Cnidarian exhibiting the Medusa body plan.
Q396.
Metagenesis, or Alteration of Generation, is observed in?
[Animal-Kingdom] [class-xi]
Hydra
Aurelia
Obelia
Adamsia
Correct Option: C [ Obelia ]
Remark: Obelia exhibits Metagenesis, where it alternates between the asexual Polyp phase and the sexual Medusa phase during its life cycle.
Q397.
Which anatomical feature in birds indicates their Reptilian ancestry?
[Animal-Kingdom] [class-xi]
Four chambered heart
Scales on hind limbs
Presence of feathers
Beak
Correct Option: B [ Scales on hind limbs ]
Remark: The presence of epidermal scales on the hind limbs of birds is a morphological trait shared with reptiles, serving as evidence of their evolutionary ancestry.
Q398.
Crop and Gizzard are specialized digestive structures found in?
[Animal-Kingdom] [class-xi]
Amphibians
Reptiles
Birds
Mammals
Correct Option: C [ Birds ]
Remark: Birds possess a crop for storing food and a gizzard for grinding food in their digestive tract. These structures are also found in some arthropods like cockroaches.
Q399.
In Ascidia, the notochord is present during which stage?
[Animal-Kingdom] [class-xi]
Throughout life
Only in larval tail
In adult head
Absent completely
Correct Option: B [ Only in larval tail ]
Remark: Ascidia belongs to the Urochordata (Tunicates). In this group, the notochord is present only in the tail of the larva and is lost during metamorphosis into the adult.
Q400.
Ascidia is a member of which subphylum?
[Animal-Kingdom] [class-xi]
Cephalochordata
Urochordata
Vertebrata
Hemichordata
Correct Option: B [ Urochordata ]
Remark: Ascidia is a classic example of Urochordata, a subphylum where the notochord is restricted to the larval tail.
