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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Q421.
Besides excretion, Kidneys in vertebrates play a crucial role in?
[Animal-Kingdom] [class-xi]
Digestion
Osmoregulation
Respiration
Reproduction
Correct Option: B [ Osmoregulation ]
Remark: Kidneys maintain the water and salt balance of the body fluids, a process known as osmoregulation, in addition to removing metabolic wastes.
Q422.
Which structure supplements respiration in birds?
[Animal-Kingdom] [class-xi]
Gills
Skin
Air sacs
Trachea
Correct Option: C [ Air sacs ]
Remark: Birds possess air sacs connected to their lungs. These sacs allow for a unidirectional flow of air, supplementing respiration and ensuring a constant supply of oxygen.
Q423.
The Air sacs in birds are directly connected to the?
[Animal-Kingdom] [class-xi]
Stomach
Lungs
Heart
Liver
Correct Option: B [ Lungs ]
Remark: The air sacs are extensions of the lungs in birds. They do not facilitate gas exchange themselves but pump air through the lungs where exchange occurs.
Q424.
The shell of Molluscs is primarily composed of?
[Animal-Kingdom] [class-xi]
Silica
Chitin
Calcium Carbonate
Cartilage
Correct Option: C [ Calcium Carbonate ]
Remark: The protective shell found in many molluscs is secreted by the mantle and is composed mainly of calcium carbonate (calcareous).
Q425.
The body of a Mollusc is divided into Head, Visceral Hump, and?
[Animal-Kingdom] [class-xi]
Thorax
Tail
Muscular Foot
Abdomen
Correct Option: C [ Muscular Foot ]
Remark: The generalized molluscan body plan consists of three main parts: an anterior head, a dorsal visceral hump (mass), and a ventral muscular foot used for locomotion.
Q426.
What type of skull is present in Amphibians and Mammals?
[Animal-Kingdom] [class-xi]
Monocondylic
Dicondylic
Tricondylic
Acondylic
Correct Option: B [ Dicondylic ]
Remark: Amphibians and Mammals possess a dicondylic skull, meaning the skull articulates with the vertebral column via two occipital condyles.
Q427.
What type of skull is typically found in Reptiles and Birds?
[Animal-Kingdom] [class-xi]
Dicondylic
Monocondylic
Multicondylic
None
Correct Option: B [ Monocondylic ]
Remark: Reptiles and Birds have a monocondylic skull, which possesses only a single occipital condyle for articulation with the atlas vertebra.
Q428.
A Dicondylic skull is characterized by having how many occipital condyles?
[Animal-Kingdom] [class-xi]
One
Two
Three
Four
Correct Option: B [ Two ]
Remark: The term "Dicondylic" refers to the presence of two occipital condyles, which are the bony protuberances connecting the skull to the neck.
Q429.
Amphioxus is commonly referred to as?
[Animal-Kingdom] [class-xi]
Lancelet
Lamprey
Hagfish
Sea squirt
Correct Option: A [ Lancelet ]
Remark: Amphioxus is a small, fish-like cephalochordate commonly known as the Lancelet due to its lance-like shape.
Q430.
Which of the following organisms has a single opening acting as both mouth and anus?
[Animal-Kingdom] [class-xi]
Earthworm
Tapeworm
Roundworm
Hookworm
Correct Option: B [ Tapeworm ]
Remark: Tapeworms (Platyhelminthes) exhibit a blind-sac body plan with an incomplete digestive system, where a single opening serves for both ingestion and egestion.
