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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Q401.
In Amphioxus, the notochord extends from?
[Animal-Kingdom] [class-xi]
Head to tail
Tail only
Proboscis to collar
Mid-dorsal only
Correct Option: A [ Head to tail ]
Remark: Amphioxus belongs to Cephalochordata. In these animals, the notochord extends from the head to the tail region and persists throughout their entire life.
Q402.
In Humans, the notochord is present during which phase?
[Animal-Kingdom] [class-xi]
Adult life
Embryonic life
Old age
Never
Correct Option: B [ Embryonic life ]
Remark: In humans (and other vertebrates), the notochord is a temporary structure present during embryonic development. It is later replaced by the vertebral column.
Q403.
Roundworms (Aschelminthes) are characterized by which type of body cavity?
[Animal-Kingdom] [class-xi]
Acoelomates
Coelomates
Pseudocoelomates
Haemocoelomates
Correct Option: C [ Pseudocoelomates ]
Remark: Roundworms possess a body cavity that is not fully lined by mesoderm; instead, the mesoderm is present as scattered pouches. This condition is called pseudocoelom.
Q404.
Platyhelminthes (Flatworms) are classified as?
[Animal-Kingdom] [class-xi]
Acoelomates
Pseudocoelomates
Coelomates
Schizocoelomates
Correct Option: A [ Acoelomates ]
Remark: Flatworms lack a body cavity between the body wall and the gut wall. Therefore, they are classified as Acoelomates.
Q405.
Scorpions respire primarily through which organ?
[Animal-Kingdom] [class-xi]
Gills
Book Gills
Book Lungs
Skin
Correct Option: C [ Book Lungs ]
Remark: Scorpions are terrestrial arthropods that respire using book lungs, which are specialized respiratory structures resembling the pages of a book.
Q406.
Starfish respire using which structure?
[Animal-Kingdom] [class-xi]
Lungs
Gills
Trachea
Book lungs
Correct Option: B [ Gills ]
Remark: Starfish (Asterias) respire using dermal branchiae or papulae, which effectively function as gills for gas exchange in the water.
Q407.
Balanoglossus is a member of which Phylum?
[Animal-Kingdom] [class-xi]
Chordata
Hemichordata
Echinodermata
Mollusca
Correct Option: B [ Hemichordata ]
Remark: Balanoglossus belongs to the Phylum Hemichordata. This group was earlier considered a subphylum under Chordata but is now placed as a separate non-chordate phylum.
Q408.
The excretory organ in Balanoglossus is the?
[Animal-Kingdom] [class-xi]
Nephridia
Kidney
Proboscis gland
Malpighian tubule
Correct Option: C [ Proboscis gland ]
Remark: Balanoglossus performs excretion through a specialized structure called the proboscis gland, which is situated in the proboscis region.
Q409.
The Glomerulus in Balanoglossus is associated with which function?
[Animal-Kingdom] [class-xi]
Digestion
Respiration
Ultrafiltration
Reproduction
Correct Option: C [ Ultrafiltration ]
Remark: The glomerulus in the proboscis of Balanoglossus is involved in ultrafiltration of blood, aiding in the process of excretion.
Q410.
Which cells in Cnidaria are totipotent and can differentiate into other cell types?
[Animal-Kingdom] [class-xi]
Cnidocytes
Interstitial cells
Choanocytes
Nerve cells
Correct Option: B [ Interstitial cells ]
Remark: Interstitial cells in Cnidarians are totipotent stem cells. They have the ability to differentiate into various other cell types, playing a key role in regeneration and growth.
