Practice Library
All MCQs
Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
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A.
Detecting water currents and nearby moving objects
B.
Producing insulin
C.
Growing feathers
D.
Making red blood cells
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Correct Answer: A. Detecting water currents and nearby moving objects
Explanation:
The lateral line is used for sensing water movement and vibration. Damage impairs orientation, schooling, prey detection, and predator avoidance.
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A.
Olfaction
B.
Photoreception
C.
Baroreception
D.
Proprioception
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Correct Answer: A. Olfaction
Explanation:
Olfactory receptors detect odor molecules. If access to receptors is blocked, smell perception decreases even if the nervous system remains intact.
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A.
Lower blood calcium
B.
Raise blood glucose
C.
Increase smell sensitivity
D.
Contract skeletal muscle directly
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Correct Answer: A. Lower blood calcium
Explanation:
Calcitonin from the thyroid helps reduce blood calcium, especially by influencing bone calcium deposition. Its role opposes parathyroid hormone.
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A.
Central processing of sensory inputs
B.
Only endocrine digestion
C.
Cuticle formation
D.
Blood clotting
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Correct Answer: A. Central processing of sensory inputs
Explanation:
The central nervous system receives and integrates sensory signals, then coordinates behavior and physiological responses through motor pathways.
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A.
Bind receptor molecules
B.
Break bones
C.
Contract tendons
D.
Open blood valves only
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Correct Answer: A. Bind receptor molecules
Explanation:
Chemical senses work when molecules interact with receptor proteins. Taste usually detects dissolved chemicals, while smell detects airborne molecules that dissolve in mucus.
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A.
Mechanoreceptor
B.
Photoreceptor
C.
Auditory receptor only
D.
Olfactory receptor
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Correct Answer: A. Mechanoreceptor
Explanation:
Stretch receptors detect mechanical deformation of tissues. In internal organs, they provide feedback about distension and physiological state.
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A.
Stimulates molting processes
B.
Lowers blood glucose in mammals
C.
Carries oxygen in hemolymph
D.
Detects water current
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Correct Answer: A. Stimulates molting processes
Explanation:
Ecdysone is an arthropod molting hormone. It initiates cuticle shedding and developmental transitions when balanced with juvenile hormone.
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A.
Lateral-line mechanoreceptors
B.
Mammalian sweat glands
C.
Thyroid follicles
D.
Bone marrow cells
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Correct Answer: A. Lateral-line mechanoreceptors
Explanation:
The lateral line detects water displacement, allowing fishes to respond quickly to pressure waves from predators, prey, or obstacles.
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A.
Mechanoreceptor
B.
Photoreceptor
C.
Osmoreceptor
D.
Endocrine receptor only
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Correct Answer: A. Mechanoreceptor
Explanation:
Touch receptors respond to mechanical deformation of skin. They are mechanoreceptors specialized for pressure or vibration rather than light.
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A.
Coordinate activities across tissues and organs
B.
Act independently without signals
C.
Avoid homeostasis
D.
Stop responding to the environment
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Correct Answer: A. Coordinate activities across tissues and organs
Explanation:
Multicellular animals require communication to coordinate movement, feeding, defense, reproduction, and internal stability across specialized tissues.
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A.
Larval characteristics
B.
Adult mammalian hair
C.
Vertebrate bone marrow
D.
Fish lateral line
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Correct Answer: A. Larval characteristics
Explanation:
Juvenile hormone helps maintain larval features. Declining juvenile hormone allows metamorphic progression toward pupal or adult stages.
Choose an option to check your answer.
A.
Well-developed lateral line
B.
Color vision only
C.
Sweat glands
D.
Thick keratin scales
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Correct Answer: A. Well-developed lateral line
Explanation:
In aquatic environments, vibrations and water movements can reveal prey even in darkness. A lateral line is specialized for this mechanosensory task.