जीव विज्ञान – Biology MCQ
जीव विज्ञान – कृषि/वन प्रवेश
Biology · Agriculture, Veterinary & Forestry Entrance · ८४० प्रश्न
८४० प्रश्न उपलब्ध। मोड छान्नुहोस्:
जीव विज्ञान: प्रश्न र उत्तर
सही लागेको विकल्पमा थिच्नुहोस्। सही भए हरियो, गलत भए रातो देखिन्छ; ३ सेकेन्डपछि सही उत्तर र व्याख्या देखिन्छ।
सही: ० / ०
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According to the sliding filament theory, during contraction of a skeletal muscle fibre:
सही उत्तर: क) The I-band shortens while the A-band keeps the same length
Actin filaments slide over myosin toward the centre, so the I-band and H-zone shorten while the A-band (myosin length) stays constant.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Vital capacity of the lungs is equal to:
सही उत्तर: ग) Tidal volume + inspiratory reserve volume + expiratory reserve volume
Vital capacity is the maximum air breathed out after a maximum inspiration: TV + IRV + ERV (it excludes the residual volume).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The increase in the capacity of blood to carry carbon dioxide when haemoglobin becomes deoxygenated in the tissues is called the:
सही उत्तर: घ) Haldane effect
Deoxygenated haemoglobin binds more CO2 and H+; this is the Haldane effect, whereas the Bohr effect is the effect of CO2 on oxygen release.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Blood serum differs from blood plasma in that serum lacks:
सही उत्तर: क) Fibrinogen and other clotting factors
Serum is the fluid left after blood clots, i.e. plasma minus fibrinogen and other clotting factors.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Dengue fever is transmitted to humans by the bite of the:
सही उत्तर: ख) Aedes mosquito
The dengue virus is spread by Aedes mosquitoes (mainly Aedes aegypti), which bite during the daytime.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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At a heart rate of 72 beats per minute, the duration of one cardiac cycle is about:
सही उत्तर: क) 0.8 second
Duration = 60 s ÷ 72 beats ≈ 0.8 s per cardiac cycle.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The delay in the conduction of the cardiac impulse, which allows the atria to empty completely before the ventricles contract, occurs at the:
सही उत्तर: ख) Atrioventricular (AV) node
The impulse is delayed for about 0.1 s at the AV node before passing to the bundle of His and the ventricles.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The dense fibrous connective tissue that attaches a skeletal muscle to a bone is called a:
सही उत्तर: ख) Tendon
Tendons join muscles to bones; ligaments join bone to bone.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The epithelium lining the walls of blood vessels and the air sacs (alveoli) of the lungs is:
सही उत्तर: ख) Simple squamous epithelium
A single layer of thin flat cells allows easy diffusion, so simple squamous epithelium lines blood vessels and alveoli.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Tooth-like placoid scales covering the skin are characteristic of:
सही उत्तर: ग) Cartilaginous fishes such as sharks
Sharks and rays (Chondrichthyes) have placoid scales; bony fishes have cycloid or ctenoid scales.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
यी अभ्यास प्रश्न हुन्, आधिकारिक प्रश्न होइनन्। पाठ्यक्रम, विज्ञापन र नतिजाका लागि सम्बन्धित निकायको आधिकारिक वेबसाइट हेर्नुहोस्। उत्तरमा गल्ती भेटे प्रश्नमुनिको "टिप्पणी / गल्ती रिपोर्ट" मा लेख्नुहोस्।
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