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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Q71.
The characteristic feature of Aves is the presence of:
[Animal-Kingdom] [class-xi]
Hair
Scales
Feathers
Mammary glands
Correct Option: C [ Feathers ]
Remark: Explanation: The defining characteristic feature of the class Aves (birds) is the presence of feathers.
Q72.
The forelimbs of birds are modified into:
[Animal-Kingdom] [class-xi]
Legs for walking
Wings
Claws for clasping
Fins for swimming
Correct Option: B [ Wings ]
Remark: Explanation: In birds, the forelimbs have been modified into wings for flight.
Q73.
The long bones of birds are hollow with air cavities, a condition known as:
[Animal-Kingdom] [class-xi]
Cartilaginous
Ossified
Pneumatic
Dense
Correct Option: C [ Pneumatic ]
Remark: Explanation: The long bones of birds are hollow and contain air cavities (pneumatic), which makes their endoskeleton light for flying.
Q74.
Homoiothermous (warm-blooded) animals are characterized by:
[Animal-Kingdom] [class-xi]
Their inability to regulate body temperature
Having a three-chambered heart
The ability to maintain a constant body temperature
Laying eggs
Correct Option: C [ The ability to maintain a constant body temperature ]
Remark: Explanation: Homoiothermous (warm-blooded) animals, like birds and mammals, are able to maintain a constant internal body temperature regardless of the external environment.
Q75.
The digestive tract of birds has additional chambers called the:
[Animal-Kingdom] [class-xi]
Pharynx and stomach
Radula and mantle
Crop and gizzard
Cloaca and colon
Correct Option: C [ Crop and gizzard ]
Remark: Explanation: The digestive tract of birds has two additional chambers: the crop for storing food and the gizzard for grinding it.
Q76.
The most unique mammalian characteristic is the presence of:
[Animal-Kingdom] [class-xi]
Hair
A four-chambered heart
Milk producing glands (mammary glands)
External ears or pinnae
Correct Option: C [ Milk producing glands (mammary glands) ]
Remark: Explanation: The most unique characteristic of mammals is the presence of milk-producing mammary glands used to nourish their young.
Q77.
Which of the following is an oviparous (egg-laying) mammal?
[Animal-Kingdom] [class-xi]
Macropus (Kangaroo)
Pteropus (Flying fox)
Balaenoptera (Blue whale)
Ornithorhynchus (Platypus)
Correct Option: D [ Ornithorhynchus (Platypus) ]
Remark: Explanation: While most mammals are viviparous (give live birth), there are exceptions. The Platypus (Ornithorhynchus) is an oviparous mammal, meaning it lays eggs.
Q78.
The skin of mammals is unique in possessing:
[Animal-Kingdom] [class-xi]
Scales
Feathers
Hair
Scutes
Correct Option: C [ Hair ]
Remark: Explanation: The skin of mammals is unique among animals for possessing hair.
Q79.
The water vascular system is a characteristic of which group?
[Animal-Kingdom] [class-xi]
Porifera
Ctenophora
Echinodermata
Chordata
Correct Option: C [ Echinodermata ]
Remark: Explanation: The water vascular system is the characteristic and most distinctive feature of the phylum Echinodermata.
Q80.
In which of the following phyla is segmentation first observed?
[Animal-Kingdom] [class-xi]
Platyhelminthes
Aschelminthes
Annelida
Arthropoda
Correct Option: C [ Annelida ]
Remark: Explanation: Body segmentation (metamerism) is first observed in the Phylum Annelida.
