Practice Library
All MCQs
Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
Choose an option to check your answer.
A.
Barrier protection against environment
B.
Production of milk
C.
Formation of feathers
D.
Synthesis of thyroid hormone
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Correct Answer: A. Barrier protection against environment
Explanation:
Damage to scales and skin weakens the body barrier. This can increase infection risk, osmotic imbalance, and injury.
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A.
Lateral line system
B.
Sweat glands
C.
Four-chambered heart
D.
Mammalian hair follicle only
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Correct Answer: A. Lateral line system
Explanation:
The lateral line system detects water movement and vibration through mechanosensory neuromasts. It helps fishes orient, avoid predators, and detect prey.
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A.
Voluntary, striated, and capable of rapid contraction
B.
Non-contractile and glandular
C.
Made only of cartilage
D.
Completely without nerves
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Correct Answer: A. Voluntary, striated, and capable of rapid contraction
Explanation:
Skeletal muscle is striated and generally under voluntary control. It produces quick, powerful contractions needed for running, jumping, or escaping predators.
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A.
Protect the body while allowing flexible swimming
B.
Replace gills during gas exchange
C.
Control endocrine secretion
D.
Produce white blood cells
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Correct Answer: A. Protect the body while allowing flexible swimming
Explanation:
Fish scales protect the body from injury and parasites while their arrangement still allows body flexion during swimming.
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A.
Nervous system
B.
Digestive system
C.
Integument alone
D.
Excretory system
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Correct Answer: A. Nervous system
Explanation:
Movement is coordinated by the nervous system, executed by muscles, and supported by skeletal structures. These systems work together for effective locomotion.
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A.
Pairs or groups of antagonistic muscles
B.
Only one tendon
C.
No joints
D.
Only endocrine glands
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Correct Answer: A. Pairs or groups of antagonistic muscles
Explanation:
Muscles generate force by contracting and pulling. Opposite movements commonly require antagonistic muscle pairs arranged around joints.
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A.
Mechanical displacement
B.
Blood glucose level
C.
Light wavelength
D.
Hormone concentration
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Correct Answer: A. Mechanical displacement
Explanation:
Neuromasts contain hair cells that bend when water moves. This converts mechanical energy into nerve signals used for aquatic sensing.
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A.
Adductor muscle
B.
Lateral line organ
C.
Endocrine pancreas
D.
Nephron
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Correct Answer: A. Adductor muscle
Explanation:
Bivalves close their shells using adductor muscles. These muscles pull the two valves together, protecting the soft body from predators and drying.
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A.
Trapping insulating air near the skin
B.
Increasing urine formation
C.
Opening all blood vessels widely
D.
Stopping all muscle activity
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Correct Answer: A. Trapping insulating air near the skin
Explanation:
Erected hair traps a layer of air that reduces heat loss. This integumentary response contributes to temperature regulation.
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A.
Reduced or absent contraction
B.
Immediate shell formation
C.
Higher antibody production
D.
Feather growth acceleration
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Correct Answer: A. Reduced or absent contraction
Explanation:
Skeletal muscles normally require neural stimulation for contraction. Without nerve impulses, voluntary movement is reduced or absent.
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A.
Reduced friction between moving surfaces
B.
More melanin in skin
C.
Less nervous control
D.
Complete bone fusion
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Correct Answer: A. Reduced friction between moving surfaces
Explanation:
Synovial fluid and smooth cartilage reduce friction in many vertebrate joints. Loss of lubrication increases wear and pain during movement.
Choose an option to check your answer.
A.
The exoskeleton and wing joints
B.
A vertebral column
C.
A hydrostatic coelom only
D.
Lymphatic vessels
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Correct Answer: A. The exoskeleton and wing joints
Explanation:
Insects use thoracic muscles that move wings through the exoskeleton and wing articulation. Their flight mechanics depend on the arthropod body plan.