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
-
The phenomenon of ‘etiolation’ in plants refers to: (a) A rapid increase in chlorophyll production due to high light intensity. (b) Abnormal growth characterized by elongated stems, pale leaves, and an upward gravitropic response seeking light. (c) The formation of adventitious roots from leaf bases. (d) The process of seed germination stimulated by ethylene hormone.
सही उत्तर: ख) Abnormal growth characterized by elongated stems, pale leaves, and an upward gravitropic response seeking light.
Etiolation is the desperate attempt of a seedling to reach light when deprived of it, resulting in elongated stems and pale leaves – option (a) describes photomorphogenesis; (c) relates to root development; (d) concerns germination hormones.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Which of the following botanical adaptations is primarily associated with drought tolerance in succulent plants like *Aloe*? (a) Large, broad leaves to maximize sunlight absorption. (b) Thick cuticles and reduced leaf surface area to minimize water loss. (c) Extensive root systems for rapid nutrient uptake. (d) High transpiration rates to cool the plant’s tissues.
सही उत्तर: ख) Thick cuticles and reduced leaf surface area to minimize water loss.
Succulents have evolved specialized features like thick cuticles and reduced leaf surfaces to drastically reduce water loss – option (a) promotes increased water loss; (c) is a general adaptation but not specifically related to drought tolerance; (d) would exacerbate the issue.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The process of ‘double fertilization’ in flowering plants, as observed in species like *Arabidopsis*, involves two sperm cells fusing with different cell types. What are the products of this unique event? (a) A diploid zygote and a triploid endosperm. (b) A diploid zygote and a haploid endosperm. (c) A triploid zygote and a diploid endosperm. (d) A tetraploid zygote and a haploid endosperm.
सही उत्तर: ख) A diploid zygote and a haploid endosperm.
Double fertilization is unique to angiosperms. One sperm fuses with the egg forming the diploid zygote, while the second sperm fuses with the central cell’s two polar nuclei, creating a triploid endosperm – options (b), (c) and (d) are incorrect as they describe different ploidy levels.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Which of the following statements best describes the concept of ‘homologous structures’ as defined by Charles Darwin? (a) Structures that have evolved from different ancestral origins to perform similar functions. (b) Structures that are identical in all species, reflecting a common ancestry. (c) Structures that share a common ancestry but may serve different functions. (d) Structures that arise de novo during development in different organisms.
सही उत्तर: ग) Structures that share a common ancestry but may serve different functions.
Homologous structures are key to Darwin's theory of evolution. They demonstrate shared ancestry despite potentially distinct current uses – options (a) and (d) describe convergent or developmental evolution respectively; (b) describes analogous structures.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The primary function of the Casparian strip in the endodermis of plant roots is to: (a) Allow free passage of water and minerals into the xylem. (b) Regulate the movement of water and mineral ions into the vascular cylinder. (c) Facilitate photosynthesis within the root cells. (d) Provide structural support to the root cortex.
सही उत्तर: ख) Regulate the movement of water and mineral ions into the vascular cylinder.
The Casparian strip is a waxy band in the endodermis that blocks the apoplastic pathway, forcing water and minerals to enter the symplast before reaching the xylem. This provides precise control over what enters the vascular system – option (a) is incorrect because it describes unrestricted movement; (c) is wrong as photosynthesis doesn’t occur in roots.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The ‘floating ribs’ of mammals primarily provide: (a) Attachment points for muscles (b) Structural support to the vertebral column (c) Protection for internal organs in the thoracic cavity (d) Increased bone density for strength
सही उत्तर: घ) (d) Increased bone density for strength
The floating ribs (specifically the 11th and 12th ribs) are uniquely attached to the sternum via their own individual ligaments, creating a space that houses the major blood vessels and parts of the diaphragm. This provides crucial protection.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
In gymnosperms like pines, pollination is often facilitated by: (a) Bees (b) Wind (c) Hummingbirds (d) Bats
सही उत्तर: ख) (b) Wind
Pine cones are adapted for wind pollination. The structure of the cone and its release mechanism relies on air currents to disperse pollen effectively. Options (a), (c) and (d) represent pollinators associated with angiosperms.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The primary function of phloem sieve cells is: (a) Water conduction (b) Transport of sugars and other organic nutrients (c) Support and rigidity of the plant stem (d) Storage of starch and proteins
सही उत्तर: ख) (b) Transport of sugars and other organic nutrients
Phloem sieve cells are specialized cells dedicated to the efficient transport of sugars (primarily sucrose) produced during photosynthesis throughout the plant. Water conduction is primarily the role of xylem vessels. Options (c) and (d) describe functions of other cell types.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
Which of the following correctly describes the role of CAM photosynthesis in plants like Opuntia? (a) It occurs primarily during daylight hours with a high rate of carbon dioxide fixation. (b) It involves rapid CO2 uptake and cyclic regeneration of RuBP. (c) It’s characterized by temporal separation of carbon assimilation and decarboxylation, concentrating CO2 in succulent stems and leaves. (d) It relies solely on C4 photosynthetic pathways.
सही उत्तर: ग) (c) It’s characterized by temporal separation of carbon assimilation and decarboxylation, concentrating CO2 in succulent stems and leaves.
CAM photosynthesis (Crassulacean Acid Metabolism) is distinct due to the temporal separation of carbon fixation and decarboxylation. Opuntia, a cactus, exemplifies this adaptation with CO2 concentrated in its succulent stem. Options (a), (b) and (d) describe different photosynthetic pathways or processes.
💬 टिप्पणी / गल्ती रिपोर्ट (०)
-
The process of exine formation in pollen grains is a result of: (a) Meiosis (b) Mitosis (c) Fragmentation (d) Pollen tube development
सही उत्तर: ख) (b) Mitosis
The exine (outer wall) of pollen grains is formed during mitosis and subsequent cell divisions. Options (a), (c) and (d) describe other processes involved in pollen development; however, it's the mitotic process that directly generates the cells which form the protective layer.
💬 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।