वनस्पति विज्ञान – Botany – Botany MCQ
वनस्पति विज्ञान – Botany – CEE प्रवेश
Botany · Medical Entrance (CEE) – Physics, Chemistry, Biology & MAT · ४०७ प्रश्न
४०७ प्रश्न उपलब्ध। मोड छान्नुहोस्:
वनस्पति विज्ञान – Botany: 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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Which of the following plant groups exhibits alternative phyllotaxy?
सही उत्तर: ग) Ferns
Alternative phyllotaxy means leaves are arranged in an alternating pattern around the stem. Dicots, like many flowering plants, typically exhibit this arrangement. Monocots have spiral phyllotaxy, ferns show multiple arrangements and bryophytes lack a true stem for leaf arrangement.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which plant hormone primarily promotes cell elongation in stems, leading to significant growth?
सही उत्तर: क) Auxin
Auxins are the key phytohormones responsible for stimulating cell elongation. While other hormones play roles in plant development, auxin's effect on stem growth is the most prominent and fundamental.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The phenomenon of geotropism refers to:
सही उत्तर: ख) The response of plant roots to gravity
Geotropism describes the directional growth responses of plants in relation to the force of gravity. Specifically, positive geotropism is root growth downwards and negative geotropism is stem growth upwards.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The presence of chalcones in certain flowers contributes to their color. These compounds are formed through:
सही उत्तर: ख) A reaction between phloem sugars and enzymes
Chalcones, produced from the reaction of phloem sugars with enzymes like chalcone synthase, are responsible for the yellow and orange colors observed in many flowers. The other options represent inaccurate processes related to color development.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The primary function of xylem vessels in plants is to transport:
सही उत्तर: ख) Water and minerals from roots to shoots
Xylem vessels are specialized cells designed for the efficient translocation of water and mineral ions absorbed by the roots to other parts of the plant. The options involving sugars or oxygen represent different transport pathways (phloem and chloroplast functions).
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Stomata opening is primarily driven by the influx of which ion into guard cells?
सही उत्तर: क) A) Potassium ions (K+)
Option A (Potassium ions (K+)) is the correct answer. The influx of K+ into guard cells, facilitated by proton pumps, increases turgor pressure and causes stomatal opening. Calcium ions play a role in signaling, chloride is less directly involved, and sodium is not a primary driver.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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The filiform apparatus, essential for pollen tube guidance into the embryo sac, is predominantly found in which type of plant?
सही उत्तर: घ) D) Angiosperms
Option C (Gymnosperms) is correct – the filiform apparatus is a unique feature of gymnosperms, particularly conifers, aiding in pollen tube penetration. Bryophytes and pteridophytes lack this specialized structure, while angiosperms have evolved more complex mechanisms for fertilization.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Ergot, a fungal disease affecting rye crops producing alkaloids like LSD, is caused by which fungus?
सही उत्तर: ख) B) *Claviceps purpurea*
Option B (*Claviceps purpurea*) is the correct answer as it is the fungus responsible for ergot production and the associated toxic alkaloids, including those that form the basis of LSD. The other fungi listed are commonly found on plants but don't cause ergot.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Which of the following plant hormones is a gas and plays a crucial role in the climacteric ripening phase of fruits?
सही उत्तर: ग) C) Ethylene
Option C (Ethylene) is correct – ethylene is a gaseous hormone responsible for fruit ripening. Auxin and abscisic acid are generally associated with growth regulation and dormancy, while cytokinin primarily affects cell division.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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Gibberellins are commonly used in barley cultivation to promote grain growth. What is the primary physiological effect of these hormones on the barley grains?
सही उत्तर: ख) B) Stimulation of stem elongation
Option B (Stimulation of stem elongation) is correct as gibberellins are well-known for their role in promoting stem growth. Options A, C, and D represent other established functions of plant hormones like florigen, ethylene, or abscisic acid respectively, which aren't the primary effect related to barley grain development.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
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