UPSC IAS Archives

1. We adopted parliamentary democracy based on the British model, but how

We adopted parliamentary democracy based on the British model, but how does our model differ from that model?

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1. As regards legislation, the British Parliament is supreme or sovereign but in India, the power of the Parliament to legislate is limited.
2. In India, matters related to the constitutionality of the Amendment of an Act of the Parliament are referred to the Constitution Bench by the Supreme Court.

Select the correct answer using the code given below.

1 only

2 only

Both 1 and 2

Neither 1 nor 2

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The correct answer is C) Both 1 and 2.

Statement 1 is correct. The British Parliament is considered supreme or sovereign in the sense that there is no codified constitution against which its laws can be tested for validity by the judiciary. In India, the power of the Parliament to legislate is limited by the written Constitution, Fundamental Rights, Directive Principles, federal structure, etc., and its laws are subject to judicial review by the Supreme Court and High Courts.
Statement 2 is correct. According to Article 145(3) of the Constitution of India, any case involving a substantial question of law as to the interpretation of the Constitution or for the purpose of hearing any reference made by the President under Article 143 shall be heard by a Bench consisting of not less than five Judges (a Constitution Bench). Matters relating to the constitutionality of Acts of Parliament or Constitutional Amendments fall under this category and are referred to a Constitution Bench by the Supreme Court.

The Indian parliamentary system, while based on the British model, incorporates unique features like judicial review (a strong, independent judiciary with the power to interpret the constitution and strike down laws) and a codified federal constitution, which significantly limit parliamentary sovereignty compared to the UK model.

2. Which one of the following is a reason why astronomical distances are

Which one of the following is a reason why astronomical distances are measured in light-years?

Distances among stellar bodies do not change.

Gravity of stellar bodies does not change.

Light always travels in straight line.

Speed of light is always same.

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The correct answer is D) Speed of light is always same.

Astronomical distances are vast, making standard units like kilometres or miles impractical. A light-year is defined as the distance light travels in one year in a vacuum. The use of light-years as a unit of distance in astronomy is based on the fact that the speed of light in a vacuum is a constant (approximately 299,792,458 meters per second). This constant speed provides a reliable basis for measuring extremely large distances across space based on time.

Options A, B, and C are incorrect. Distances between celestial bodies do change (due to cosmic expansion, orbital motion, etc.). Gravity of stellar bodies also changes depending on mass distribution and distance. While light travels in approximately straight lines in uniform media, it can be bent by gravity (gravitational lensing). The constancy of the speed of light is the fundamental principle behind using light-years to measure distance.

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3. ‘Triclosan’, considered harmful when exposed to high levels for a long

‘Triclosan’, considered harmful when exposed to high levels for a long time, is most likely present in which of the following?

Food preservatives

Fruit-ripening substances

Reused plastic containers

Toiletries

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Triclosan is an antibacterial and antifungal chemical that was widely used in various consumer products aimed at reducing bacterial contamination. These products included antibacterial soaps, hand sanitizers, toothpastes, mouthwashes, cosmetics, and detergents. Its use has been restricted or banned in some applications (like over-the-counter antiseptic washes) in certain regions due to concerns about potential health effects and its contribution to antibiotic resistance. Therefore, triclosan is most likely found in toiletries and personal care products.

– Triclosan is an antimicrobial agent.
– It was commonly added to antibacterial soaps, toothpastes, mouthwashes, and other personal care products.
– Concerns exist regarding its health effects and environmental impact.

While triclosan was prevalent in many consumer goods, regulations in some countries have limited its use. The term ‘toiletries’ encompasses personal hygiene products, which were a major category where triclosan was incorporated. It is not typically used as a food preservative, fruit-ripening substance, or a structural component of common plastic containers like those intended for reuse.

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4. Bisphenol A (BPA), a cause of concern, is a structural/key component i

Bisphenol A (BPA), a cause of concern, is a structural/key component in the manufacture of which of the following kinds of plastics?

Low-density polyethylene

Polycarbonate

Polyethylene terephthalate

Polyvinyl chloride

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Bisphenol A (BPA) is a chemical compound used as a building block (monomer) primarily in the production of polycarbonate plastics and epoxy resins. Polycarbonate is a strong, transparent, and durable thermoplastic polymer used in various products, including some food containers, water bottles, baby bottles (now restricted in many places), CDs, DVDs, and eyeglasses. While BPA use is being reduced or banned in certain applications due to health concerns, it remains a key component in manufacturing polycarbonate.

– Bisphenol A (BPA) is an industrial chemical.
– It is a key structural component in the manufacture of polycarbonate plastic and epoxy resins.
– Polycarbonate is used in various consumer products.

Concerns about BPA stem from its potential to leach into food and beverages from containers and its classification as an endocrine disruptor, meaning it can interfere with hormonal systems. Many products are now marketed as “BPA-free,” indicating the use of alternative materials or manufacturing processes. LDPE, PET, and PVC are different types of plastics manufactured using different monomers and processes, and do not typically contain BPA.

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5. The term ‘ACE2’ is talked about in the context of

The term ‘ACE2’ is talked about in the context of

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genes introduced in the genetically modified plants

development of India's own satellite navigation system

radio collars for wildlife tracking

spread of viral diseases

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The term ‘ACE2’ stands for Angiotensin-converting enzyme 2. This enzyme is a protein found on the surface of many cells, particularly in the lungs, heart, kidneys, and intestines. It became widely known because it serves as the primary receptor that the SARS-CoV-2 virus (which causes COVID-19) uses to enter human cells. Therefore, ACE2 is talked about extensively in the context of the spread of viral diseases, specifically COVID-19.

– ACE2 is a protein enzyme found on cell surfaces.
– It acts as a receptor for coronaviruses, including SARS-CoV-2.
– The binding of the virus to ACE2 is the initial step in cellular infection.

ACE2 is part of the renin-angiotensin system (RAS), which plays a crucial role in regulating blood pressure and fluid balance. Research is ongoing to understand the complex interaction between SARS-CoV-2 and ACE2, and how it affects the RAS and contributes to the severity of COVID-19 disease.

6. With reference to street-lighting, how do sodium lamps differ from LED

With reference to street-lighting, how do sodium lamps differ from LED lamps?

1. Sodium lamps produce light in 360 degrees but it is not so in the case of LED lamps.
2. As street-lights, sodium lamps have longer life span than LED lamps.
3. The spectrum of visible light from sodium lamps is almost monochromatic while LED lamps offer significant colour advantages in street-lighting.

Select the correct answer using the code given below.

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3 only

2 only

1 and 3 only

1, 2 and 3

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Answer is Wrong!

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Statement 1 is correct. Traditional sodium lamps (like high-pressure sodium lamps) emit light omnidirectionally (in all directions), requiring reflectors to direct light downwards onto the street. LED lamps, by contrast, are inherently directional light sources, meaning they emit light primarily in a specific direction (forward). This directional nature allows for more efficient targeting of light where needed. Statement 2 is incorrect. LED lamps generally have a much longer lifespan (typically 50,000 to 100,000+ hours) compared to sodium lamps (typically 20,000 to 30,000 hours). Statement 3 is correct. High-pressure sodium lamps produce a predominantly yellow-orange light, resulting in poor color rendering (objects appear unnatural or monochrome). LED lamps can produce white light with various color temperatures and offer significantly better color rendering index (CRI), which improves visibility, recognition of objects and colors, and safety under street lighting.

– Sodium lamps emit light omnidirectionally, while LEDs are directional.
– LEDs have a significantly longer lifespan than sodium lamps.
– Sodium lamps provide poor color rendering (monochromatic light), while LEDs offer much better color rendering.

LED street lights also offer advantages in terms of energy efficiency (lower power consumption), instant on/off capability, dimmability, and environmental benefits (no mercury). These factors have led to a widespread shift from sodium vapor lamps to LED technology for street lighting globally.

7. Water can dissolve more substances than any other liquid because

Water can dissolve more substances than any other liquid because

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it is dipolar in nature

it is a good conductor of heat

it has high value of specific heat

it is an oxide of hydrogen

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Water is often called the “universal solvent” because it can dissolve a wide variety of substances. This ability is primarily due to its dipolar nature. The water molecule (H₂O) has a bent shape with the oxygen atom having a partial negative charge and the two hydrogen atoms having partial positive charges. This creates a polar molecule with distinct positive and negative ends. These charged ends can attract and interact with the charged or partially charged parts of other molecules, effectively surrounding and separating them (solvation), thus dissolving them.

– Water is a polar molecule due to unequal sharing of electrons between oxygen and hydrogen atoms.
– The polarity creates partial positive and negative charges on the molecule (dipole).
– The dipolar nature allows water to form hydrogen bonds and to effectively hydrate and dissolve other polar and ionic substances.

While water’s high specific heat and other properties are important for various natural processes, they are not the reason for its dissolving capacity. Being an oxide of hydrogen describes its chemical composition but not the mechanism of solvation. Water’s polarity is key to its role as a solvent in biological systems and the environment.

8. “Leaf litter decomposes faster than in any other biome and as a result

“Leaf litter decomposes faster than in any other biome and as a result the soil surface is often almost bare. Apart from trees, the vegetation is largely composed of plant forms that reach up into the canopy vicariously, by climbing the trees or growing as epiphytes, rooted on the upper branches of trees.” This is the most likely description of

coniferous forest

dry deciduous forest

mangrove forest

tropical rain forest

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The description perfectly matches the characteristics of a tropical rainforest. Fast leaf litter decomposition occurs due to the high temperatures and humidity, leading to rapid nutrient cycling and often a thin or almost bare soil surface layer of organic matter. The dense canopy in tropical rainforests limits light penetration to the forest floor, leading to intense competition for light. This favors plant forms that can reach the canopy by climbing (lianas) or growing on other plants (epiphytes) to access sunlight. These features are not characteristic of coniferous forests (slow decomposition in cold climates), dry deciduous forests (decomposition limited during dry season, fewer epiphytes/climbers), or mangrove forests (unique adaptations to saline, waterlogged conditions).

– High temperature and humidity in tropical rainforests lead to rapid decomposition.
– Rapid decomposition results in nutrients being quickly absorbed by plants, leaving limited organic matter on the soil surface.
– Light competition in the dense canopy drives the evolution of climbers and epiphytes as prominent plant forms.

Tropical rainforests are characterized by high biodiversity, high rainfall, and warm temperatures throughout the year. The rapid nutrient cycling means that much of the ecosystem’s nutrients are stored in the biomass of the plants rather than in the soil itself. Disturbances like deforestation can lead to rapid soil degradation as nutrients are washed away or lost.

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9. In the context of India’s preparation for Climate-Smart Agriculture, c

In the context of India’s preparation for Climate-Smart Agriculture, consider the following statements:

1. The ‘Climate-Smart Village’ approach in India is a part of a project led by the Climate Change, Agriculture and Food Security (CCAFS), an international research programme.
2. The project of CCAFS is carried out under Consultative Group on International Agricultural Research (CGIAR) headquartered in France.
3. The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) in India is one of the CGIAR’s research centres.

Which of the statements given above are correct?

1 and 2 only

2 and 3 only

1 and 3 only

1, 2 and 3

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All three statements are correct. The ‘Climate-Smart Village’ (CSV) approach was indeed pioneered by the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS). CCAFS is an international research program focusing on climate change impacts on agriculture. CGIAR (Consultative Group on International Agricultural Research) is a global partnership that unites international organizations engaged in research for a food-secure future. The CGIAR System Organization is legally registered in France, with its main office in Montpellier, and it coordinates the activities of the various CGIAR Research Centers. ICRISAT (International Crops Research Institute for the Semi-Arid Tropics), located in Hyderabad, India, is one of the CGIAR’s research centers.

– Climate-Smart Agriculture (CSA) aims to increase productivity and incomes, adapt and build resilience to climate change, and reduce greenhouse gas emissions.
– The Climate-Smart Village approach demonstrates CSA practices at the community level.
– CCAFS is a leading international research program in this area.
– CGIAR is a global network of agricultural research organizations.
– ICRISAT is a CGIAR research center based in India.

CGIAR supports 15 research centers worldwide that conduct research on various aspects of agriculture, food security, and climate change. The CSV model involves working with local communities to identify and implement appropriate CSA technologies and practices based on local conditions and needs. These often include improved crop varieties, water management techniques, sustainable soil management, and diversification of farming systems.

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10. Consider the following statements: 1. In the tropical zone, the west

Consider the following statements:

1. In the tropical zone, the western sections of the oceans are warmer than the eastern sections owing to the influence of trade winds.
2. In the temperate zone, westerlies make the eastern sections of oceans warmer than the western sections.

Which of the statements given above is/are correct?

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1 only

2 only

Both 1 and 2

Neither 1 nor 2

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Answer is Wrong!

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UPSC IAS – 2021

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Statement 1 is correct. In the tropical zone, the trade winds blow from east to west, pushing warm surface water towards the western side of ocean basins. This leads to a pile-up of warm water on the western side, making it warmer than the eastern side. Examples include the Gulf Stream (western Atlantic) and Kuroshio Current (western Pacific). Statement 2 is incorrect. In the temperate zone, while westerlies are the prevailing winds, the general ocean circulation patterns (driven by a combination of winds, Earth’s rotation – Coriolis effect, and density differences) result in warm currents flowing poleward on the western side of ocean basins and cold currents flowing equatorward on the eastern side. Therefore, the western sections of ocean basins are generally warmer than the eastern sections in the temperate zone as well, due to the transport of heat from the tropics. For example, the western side of the North Atlantic (near the US East Coast) is warmer than the eastern side (near Europe) at the same latitude due to the Gulf Stream. However, the Gulf Stream carries this warm water to Europe’s western coast, making Europe warmer than North America at similar latitudes. The statement says “eastern sections of oceans warmer than the western sections” which is generally false in the temperate zone for the ocean basin as a whole.

– Trade winds cause warm water to accumulate on the western side of tropical ocean basins.
– Westerlies are dominant winds in temperate zones but oceanic circulation patterns maintain warmer waters on the western side of ocean basins and colder waters on the eastern side in these latitudes.
– Boundary currents like the Gulf Stream and Kuroshio are warm western boundary currents flowing poleward.
– Boundary currents like the California Current and Canary Current are cold eastern boundary currents flowing equatorward.

The large-scale wind-driven surface ocean circulation forms gyres. In both the tropical and temperate zones, within these gyres, there are strong, narrow western boundary currents (like the Gulf Stream) and weaker, broader eastern boundary currents (like the California Current). These dynamics contribute to the western side of ocean basins being generally warmer than the eastern side in both zones.