Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
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Double circulation separates pulmonary and systemic circuits. Blood can be oxygenated in lungs and then pumped at high pressure to body tissues.
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Ecdysone promotes molting, but juvenile hormone helps determine whether the molt remains larval or proceeds toward metamorphosis. Lower juvenile hormone permits adult development.
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Insulin release after high glucose reduces the original stimulus by lowering blood glucose. This is a classic negative feedback mechanism for homeostasis.
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Adrenaline binds receptors on heart and blood vessel cells, producing rapid cardiovascular effects. Hormonal action depends on receptor-bearing target tissues.
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The optic nerve carries signals from retinal photoreceptors to the brain. Damage reduces visual input and can impair reflexes that depend on light detection.
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Taste is a chemical sense. Food molecules must dissolve and contact taste receptor cells before nerve signals can be generated.
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The lateral line detects water displacement produced by nearby animals. It helps schooling fishes maintain spacing and direction when vision is limited.
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Sensory neurons carry information from receptors toward the central nervous system. Damage prevents normal sensory signals from reaching processing centers.
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Closing the shell protects soft molluscan tissues from predators and drying. The behavior depends on adductor muscles and the protective shell.
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Comparative skeletons show adaptations for swimming, jumping, flying, or running. Form-and-function analysis explains why skeletons differ among fish, amphibians, birds, and mammals.
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In arthropods, the exoskeleton forms the body wall and provides internal attachment points for muscles. This arrangement allows jointed appendage movement and body support.
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Amphibian skin is thin, moist, and richly supplied with blood vessels, making cutaneous gas exchange possible. Fish rely mainly on gills, while frog skin can supplement respiration.
