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
-
Annual rings in tree trunks are formed due to variations in: (A) Root length (B) Stem diameter (C) Growth rate, influenced by seasonal changes in temperature and precipitation (D) Leaf size
सही उत्तर: ग) (C) Growth rate, influenced by seasonal changes in temperature and precipitation
Annual rings are created by the annual growth cycle of trees. The rapid growth during warmer months leads to a lighter-colored ring, while slower growth during colder months creates a darker ring. The tree’s diameter varies during this process.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
In rice and wheat, pollen grains typically lose their viability within approximately: (A) 1-2 days (B) 7-14 days (C) 30-60 days (D) 90-120 days
सही उत्तर: ख) (B) 7-14 days
Pollen viability is significantly reduced after fertilization. Within a few days of successful pollination, the pollen grains lose their ability to germinate and fertilize ovules. The values are between one to two days.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Which of the following statements accurately describes the composition of the exine of a pollen grain? (A) Primarily cellulose and pectin (B) A complex mixture of proteins, lipids, and polysaccharides (C) Primarily sporopollenin, a highly resistant polymer (D) Mostly starch granules for energy storage
सही उत्तर: ग) (C) Primarily sporopollenin, a highly resistant polymer
The exine is the tough outer layer of a pollen grain. It’s primarily composed of sporopollenin, a complex polymer providing protection and resistance to degradation, making it exceptionally durable. Options (A) and (D) describe different components present in the inner layers.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The primary function of phloem tissue in plants is: (A) Support and transport of water and minerals (B) Transport of sugars produced during photosynthesis (C) Protection against herbivores and pathogens (D) Reproduction through seed formation
सही उत्तर: ख) (B) Transport of sugars produced during photosynthesis
Phloem is responsible for transporting organic compounds, primarily sucrose, throughout the plant. The other options describe functions of different tissue types like xylem or protective structures. Option (A) describes Xylem function.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The process of pollination, where pollen grains are transferred from the stamen to the pistil, involves various agents. Which of these represents a primary agent of wind pollination?
सही उत्तर: ग) Pollen carried by air currents
Wind pollination (anemophily) relies on the passive movement of pollen grains through the air. While bees and butterflies are pollinators, their involvement isn't direct transmission by wind; spiders don’t typically play a role in pollen transfer.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The phenomenon of crassulaceacidic acid metabolism (CAM) is primarily observed in which plant types?
सही उत्तर: ख) C4 plants adapting to arid environments
CAM photosynthesis allows plants to fix CO2 at night when temperatures are cooler and humidity is higher, minimizing water loss. This adaptation is characteristic of C4 plants thriving in stressful conditions like drought. Option 2 is correct; options 3 & 4 describe different photosynthetic pathways or plant adaptations.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The Calvin cycle begins with the carboxylation of RuBP by CO2. What molecule acts as the initial CO2 acceptor in this process?
सही उत्तर: क) RuBisCO
RuBisCO (RuDP carboxylase/oxygenase) is the enzyme that catalyzes the first major step of carbon fixation in the Calvin cycle – the attachment of CO2 to RuBP. The other options are intermediates or products within the cycle, not the initial acceptor.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The ‘foolish seedling’ (bakanae) disease in rice was first observed and studied due to the discovery of: (A) A bacterial pathogen (B) Fungal hyphae within the developing embryo (C) Viral infection of the root system (D) Parasitic nematode infestation
सही उत्तर: ग) (C) Viral infection of the root system
The bakanae disease is caused by the fungus *Fusarium oxysporum*, which invades the rice embryo and disrupts development. The presence of fungal hyphae was the key discovery.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The pressure flow hypothesis of translocation in phloem explains movement through a process involving: (A) Active transport of sugars directly into sieve tubes. (B) Osmotic pressure gradient driving the movement of fluids containing sugars. (C) Bulk flow of water moving along concentration gradients. (D) Capillary action drawing sugars up the xylem vessels.
सही उत्तर: ग) (C) Bulk flow of water moving along concentration gradients.
The pressure flow hypothesis posits that a high pressure created by sugar loading into phloem siphons sugars to areas of higher demand, driven by osmotic pressure changes.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The characteristic red coloration of ripe tomatoes and carrots arises from pigments belonging to which group? (A) Chlorophylls (B) Carotenoids (C) Anthocyanins (D) Phycobilins
सही उत्तर: ग) (C) Anthocyanins
Carotenoids, specifically beta-carotene and lycopene, are responsible for the red and orange colors in tomatoes and carrots. Chlorophylls are green pigments.
💬 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।
नमस्ते! पाठ्यक्रम, सामान्य ज्ञान, भाषा परीक्षा वा कुनै प्रश्नको उत्तर बुझ्न सोध्नुहोस्।
AI ले गल्ती गर्न सक्छ। महत्वपूर्ण कुरा आधिकारिक स्रोतमा जाँच्नुहोस्।