UPSC Prelims 2020 Question Paper
Explore the complete solved question paper for UPSC Prelims 2020 featuring 100 solved questions with bilingual (English & Hindi) explanations, official answer key, and subject weightage breakdown.
In India, separation of judiciary from the executive is enjoined by
Detailed Explanation:
Answer: Option 2 — a Directive Principle of State Policy.
Article 50 of the Indian Constitution, which falls under the Directive Principles of State Policy (Part IV), explicitly directs the State to take steps to separate the judiciary from the executive in the public services of the State. This provision aims to ensure judicial independence and impartial administration of justice.
📝 Short Notes: Separation of Judiciary from Executive
- Article 50: Part of Directive Principles of State Policy (Part IV), mandates separation of judiciary from executive in public services
- Nature: Not legally enforceable but fundamental in governance (Article 37)
- Purpose: Ensures judicial independence, prevents executive interference, promotes impartial justice delivery
- Implementation: Most states have separated judiciary from executive at district and subordinate levels
- Contrast with Legislature: Separation from legislature is ensured through specific Constitutional provisions (Articles 121, 122, 211, 212)
- Historical Context: Borrowed from Irish Constitution; reflects commitment to rule of law
Consider the following statements:
- The Constitution of India defines its ‘basic structure’ in terms of federalism, secularism, fundamental rights and democracy.
- The Constitution of India provides for ‘judicial review’ to safeguard the citizens’ liberties and to preserve the ideals on which the Constitution is based.
Which of the statements given above is/are correct?
Detailed Explanation:
Answer: Option 4 — Neither 1 nor 2
Both statements are incorrect because they use the word 'defines' and 'provides', suggesting explicit mention in the Constitution, which is not the case. The basic structure doctrine and judicial review are both judicially evolved concepts derived from constitutional interpretation, not explicitly defined provisions.
❌ Statement 1 – Incorrect: The Constitution does not define its 'basic structure' anywhere in its text. The basic structure doctrine was judicially evolved by the Supreme Court in Kesavananda Bharati v. State of Kerala (1973), identifying unamendable core features like federalism, secularism, and democracy.
❌ Statement 2 – Incorrect: The Constitution does not explicitly 'provide for' judicial review as a named power. Judicial review is an implicit power derived from Articles 13, 32, 226, and other provisions, enabling courts to examine the constitutionality of laws and executive actions.
📝 Short Notes: Basic Structure Doctrine and Judicial Review
| Concept | Key Details |
|---|---|
| Basic Structure Doctrine | Evolved in Kesavananda Bharati v. State of Kerala (1973); holds that certain fundamental features of the Constitution cannot be amended by Parliament under Article 368 |
| Core Elements | Supremacy of Constitution, Rule of law, Independence of judiciary, Federalism, Secularism, Separation of powers, Sovereign democratic republic |
| Judicial Review | Power of courts to examine constitutional validity of legislative enactments and executive orders |
| Constitutional Basis | Articles 13 (laws inconsistent with fundamental rights void), 32 (SC jurisdiction), 226 (HC jurisdiction), 131-136, 143, 246 |
| Types | Judicial review of constitutional amendments, legislative actions, and executive actions |
Which one of the following categories of Fundamental Rights incorporates protection against untouchability as a form of discrimination?
Detailed Explanation:
Answer: Option 4 — Right to Equality
The Right to Equality (Articles 14-18) includes Article 17, which specifically abolishes untouchability and prohibits its practice in any form. Untouchability is fundamentally a form of social discrimination that violates the basic principle of equality guaranteed to all citizens under the Constitution.
📝 Short Notes: Right to Equality (Articles 14-18)
| Article | Provision |
|---|---|
| Article 14 | Equality before law and equal protection of laws |
| Article 15 | Prohibition of discrimination on grounds of religion, race, caste, sex, or place of birth |
| Article 16 | Equality of opportunity in matters of public employment |
| Article 17 | Abolition of untouchability and prohibition of its practice in any form |
| Article 18 | Abolition of titles (except military and academic distinctions) |
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Which part of the Constitution of India declares the ideal of Welfare State?
Detailed Explanation:
Answer: Option 1 — Directive Principles of State Policy
The Directive Principles of State Policy (DPSP) declare the ideal of a Welfare State in the Indian Constitution. Article 38(1) mandates that the State shall strive to promote the welfare of the people by securing and protecting a social order in which social, economic, and political justice shall inform all institutions of national life. These principles guide the State in establishing policies aimed at socio-economic welfare, making them the constitutional foundation of the Welfare State concept.
📝 Short Notes: Welfare State and Constitutional Provisions
- Directive Principles of State Policy (Part IV): Non-justiciable guidelines for the State to establish a just society and welfare state
- Article 38: State to secure a social order for the promotion of welfare of the people with justice (social, economic, political)
- Article 39: Directs the State to ensure adequate means of livelihood, equal pay for equal work, and prevent concentration of wealth
- Article 41: Right to work, education, and public assistance in cases of unemployment, old age, sickness, and disablement
- Article 42: Provision for just and humane conditions of work and maternity relief
- Article 43: Living wage and conditions of work ensuring a decent standard of life
- Welfare State Concept: State actively intervenes to promote social and economic welfare of citizens, ensuring equitable distribution of resources and opportunities
- Contrast with Fundamental Rights: While Fundamental Rights are justiciable individual rights, DPSPs are programmatic goals for state policy to achieve welfare objectives
Consider the following pairs:
| River | Flows into |
|---|---|
| 1. Mekong | Andaman Sea |
| 2. Thames | Irish Sea |
| 3. Volga | Caspian Sea |
| 4. Zambezi | Indian Ocean |
Which of the pairs given above is/are correctly matched?
Detailed Explanation:
Answer: Option 3 — 3 and 4 only
This question tests the knowledge of major world rivers and their drainage systems. Out of the four pairs, only pairs 3 and 4 are correctly matched, while pairs 1 and 2 contain errors regarding the water bodies into which these rivers flow.
❌ Pair 1 – Incorrect: The Mekong River flows into the South China Sea, not the Andaman Sea. It originates in the Tibetan Plateau and passes through China, Myanmar, Laos, Thailand, Cambodia, and Vietnam.
❌ Pair 2 – Incorrect: The Thames River flows into the North Sea, not the Irish Sea. It flows entirely within England.
✅ Pair 3 – Correct: The Volga River, Europe's longest river, originates in Russia and correctly flows into the Caspian Sea.
✅ Pair 4 – Correct: The Zambezi River originates in Zambia and flows through several countries before emptying into the Indian Ocean via Mozambique.
📝 Short Notes: Major World Rivers and Their Drainage
| River | Region/Countries | Drains Into | Special Features |
|---|---|---|---|
| Mekong | Tibet, China, Myanmar, Laos, Thailand, Cambodia, Vietnam | South China Sea | Asia's 7th longest river; vital for Southeast Asian fisheries |
| Thames | England, UK | North Sea | Flows through London; historically significant for British trade |
| Volga | Russia | Caspian Sea | Europe's longest river (3,530 km); major transport route |
| Zambezi | Zambia, Angola, Namibia, Botswana, Zimbabwe, Mozambique | Indian Ocean | Africa's 4th longest; Victoria Falls located on this river |
| Amazon | Peru, Brazil, Colombia | Atlantic Ocean | World's largest river by discharge volume |
| Nile | Uganda, Sudan, Egypt | Mediterranean Sea | World's longest river (disputed with Amazon) |
With reference to the current trends in the cultivation of sugarcane in India, consider the following statements:
- A substantial saving in seed material is made when ‘bud chip settlings’ are raised in a nursery and transplanted in the main field.
- When direct planting of setts is done, the germination percentage is better with singlebudded setts as compared to setts with many buds.
- If bad weather conditions prevail when setts are directly planted, single-budded setts have better survival as compared to large setts.
- Sugarcane can be cultivated using settlings prepared from tissue culture.
Which of the statements given above is/are correct?
Detailed Explanation:
Answer: Option 3 — 1 and 4 only
This question tests knowledge of modern sugarcane cultivation techniques in India. Statements 1 and 4 correctly describe cost-effective and scientifically advanced methods of sugarcane propagation, while statements 2 and 3 incorrectly characterize the performance of single-budded setts.
✅ Statement 1 – Correct: The bud chip method involves raising settlings in a nursery from individual buds before transplanting, resulting in substantial savings in seed material (up to 75-80% reduction) compared to conventional sett planting.
❌ Statement 2 – Incorrect: Multi-budded setts have better germination percentage than single-budded setts because multiple buds increase the probability of successful shoot emergence, providing redundancy if one bud fails.
❌ Statement 3 – Incorrect: Under adverse weather conditions, large multi-budded setts have better survival rates because they contain more stored nutrients and moisture reserves, making them more resilient than single-budded setts which are vulnerable to stress.
✅ Statement 4 – Correct: Tissue culture technology is successfully employed in sugarcane cultivation to produce disease-free, genetically uniform settlings that ensure higher yields and rapid multiplication of elite varieties.
📝 Short Notes: Modern Sugarcane Cultivation Methods
| Method | Key Features | Advantages |
|---|---|---|
| Bud Chip Method | Single buds raised in nursery, then transplanted | 75-80% reduction in seed material; cost-effective; better disease control |
| Tissue Culture | In-vitro propagation of disease-free plantlets | Rapid multiplication; genetic uniformity; disease-free planting material |
| Conventional Sett Method | 3-budded setts directly planted in field | Better germination and survival under stress; traditional and simple |
| Single-budded Setts | Individual buds planted directly | Some seed saving but lower germination and survival compared to multi-budded setts |
- Seed Material Requirement: Conventional method requires 6-10 tonnes/hectare; bud chip method reduces it to 1.5-2 tonnes/hectare
- Germination Factor: Multi-budded setts provide redundancy—if one bud fails, others can sprout
- Stress Tolerance: Larger setts with more buds store more nutrients and moisture, ensuring better survival under drought or pest attack
- Indian Context: India is the second-largest sugarcane producer globally; adoption of modern techniques like bud chip and tissue culture is being promoted to reduce costs and increase productivity
With reference to Ocean Mean Temperature (OMT), which of the following statements is/are correct?
- OMT is measured up to a depth of 26°C isotherm which is 129 meters in the south-western Indian Ocean during January-March.
- OMT collected during January-March can be used in assessing whether the amount of rainfall in monsoon will be less or more than a certain long-term mean.
Select the correct answer using the code given below:
Detailed Explanation:
Answer: Option 2 — 2 only
Ocean Mean Temperature (OMT) is measured up to the depth of the 26°C isotherm and serves as a reliable indicator of upper ocean heat content for monsoon prediction. Statement 1 is incorrect because the depth of the 26°C isotherm in the south-western Indian Ocean during January-March is approximately 59 meters, not 129 meters. Statement 2 is correct as OMT data collected during January-March can indeed be used to assess whether Indian Summer Monsoon Rainfall (ISMR) will be above or below the long-term mean.
❌ Statement 1 – Incorrect: The depth of 26°C isotherm is approximately 59 meters in the south-western Indian Ocean during January-March, not 129 meters.
✅ Statement 2 – Correct: OMT collected during January-March is used to predict whether ISMR will be above or below the long-term mean, making it a valuable forecasting tool.
📝 Short Notes: Ocean Mean Temperature (OMT)
- Definition: OMT is the average temperature of the ocean water column from the surface down to the depth of the 26°C isotherm (D26).
- Significance: OMT is a more stable and reliable indicator of upper ocean heat content compared to Sea Surface Temperature (SST) alone.
- Monsoon Prediction: Research by Indian Institute of Tropical Meteorology (IITM) shows that OMT data from January-March in the south-western Indian Ocean can predict Indian Summer Monsoon Rainfall with greater accuracy.
- Depth Measurement: The 26°C isotherm depth varies spatially and temporally; in the south-western Indian Ocean during January-March, it is approximately 59 meters.
- Advantage over SST: Unlike SST which can fluctuate rapidly due to surface processes, OMT represents the integrated heat content of the upper ocean layer.
- Predictive Value: Higher OMT values generally indicate favorable conditions for above-normal monsoon rainfall over India.
Consider the following statements:
- Jet streams occur in the Northern Hemisphere only.
- Only some cyclones develop an eye.
- The temperature inside the eye of a cyclone is nearly 10°C lesser than that of the surroundings.
Which of the statements given above is/are correct ?
Detailed Explanation:
Answer: Option 3 — 2 only
Only statement 2 is correct. Jet streams occur in both hemispheres, not just the Northern Hemisphere. The eye of a cyclone is warmer than its surroundings due to adiabatic heating from subsiding air, not cooler. Only strong tropical cyclones develop a well-defined eye structure.
✅ Statement 1 – Incorrect: Jet streams occur in both the Northern and Southern Hemispheres at high altitudes (10-15 km), not exclusively in the Northern Hemisphere.
✅ Statement 2 – Correct: Only some cyclones, particularly intense tropical cyclones (hurricanes/typhoons), develop a well-defined eye at their center.
❌ Statement 3 – Incorrect: The eye of a cyclone is warmer (2-10°C higher) than the surroundings due to adiabatic heating from subsiding air, not cooler.
📝 Short Notes: Tropical Cyclones and Jet Streams
| Feature | Details |
|---|---|
| Jet Streams | Fast-moving air currents at 10-15 km altitude; occur in both hemispheres; located at boundaries between troposphere and stratosphere; influence weather patterns |
| Cyclone Eye | Calm, low-pressure center found only in intense cyclones; characterized by clear skies, light winds, and warmer temperatures |
| Eye Temperature | 2-10°C warmer than surroundings due to subsiding air compressing and heating adiabatically |
| Eye Wall | Ring of thunderstorms surrounding the eye; contains the strongest winds and heaviest rainfall |
| Cyclone Formation | Requires sea surface temperature >27°C, Coriolis force, low wind shear, and atmospheric instability |
Siachen Glacier is situated to the
Detailed Explanation:
Answer: Option 4 — North of Nubra Valley
The Siachen Glacier is located in the eastern Karakoram range of the Himalayas, positioned north of the Nubra Valley in Ladakh. It is the world's highest battlefield, where India maintains a military presence at altitudes exceeding 5,400 meters.
✅ Option 4 – Correct: Siachen Glacier lies directly north of Nubra Valley in the eastern Karakoram range.
❌ Option 1 – Incorrect: Aksai Chin is located to the east of Ladakh, whereas Siachen is to the northwest of it.
❌ Option 2 – Incorrect: Leh is situated to the south of Siachen Glacier, not to its west.
❌ Option 3 – Incorrect: Gilgit is in the Gilgit-Baltistan region, west of Siachen Glacier, not to its south.
📝 Short Notes: Siachen Glacier and Surrounding Geography
| Feature | Details |
|---|---|
| Location | Eastern Karakoram range, northern Ladakh |
| Length | Approximately 76 km (second longest glacier in non-polar regions) |
| Altitude | Ranges from 5,400 m to over 7,000 m |
| Strategic Importance | World's highest battlefield; controlled by India since Operation Meghdoot (1984) |
| Surrounding Areas | North of Nubra Valley, east of Gilgit-Baltistan, northwest of Aksai Chin, north of Leh |
| River Source | Nubra River originates from Siachen Glacier |
Consider the following minerals:
- Bentonite
- Chromite
- Kyanite
- Sillimanite
In India, which of the above is/are officially designated as major minerals?
Detailed Explanation:
Answer: Option 4 — 2, 3 and 4 only
In India, major minerals are those specified in the First Schedule of the Mines and Minerals (Development and Regulation) Act, 1957. Bentonite is classified as a minor mineral, while Chromite, Kyanite, and Sillimanite are all major minerals.
1. Bentonite – Minor Mineral: Bentonite is a clay mineral used in drilling mud, foundry sand, and civil engineering applications. It is listed under minor minerals.
2. Chromite – Major Mineral ✅: Chromite is the only ore of chromium and is essential for manufacturing stainless steel and various alloys. It is a major mineral.
3. Kyanite – Major Mineral ✅: Kyanite is a refractory mineral used in ceramics and high-temperature industrial applications. It is classified as a major mineral.
4. Sillimanite – Major Mineral ✅: Sillimanite is another refractory mineral with applications in metallurgy and industrial furnaces. It is a major mineral.
📝 Short Notes: Major vs Minor Minerals in India
| Aspect | Major Minerals | Minor Minerals |
|---|---|---|
| Legal Framework | Specified in First Schedule of MMDR Act, 1957 | Specified in Second Schedule of MMDR Act, 1957 |
| Regulatory Authority | Central Government | State Government |
| Examples | Chromite, Kyanite, Sillimanite, Coal, Iron ore, Manganese, Gold, Diamond | Bentonite, Limestone (except for cement), Building stones, Gravel, Sand, Clay |
| Strategic Importance | High economic and industrial significance | Local importance, construction materials |
| Number | 64 minerals listed | Varies by state notification |
- Refractory Minerals: Kyanite and Sillimanite are aluminum silicate minerals with high heat resistance, crucial for refractory (heat-resistant) materials.
- Chromite in India: India has significant chromite reserves, mainly in Odisha (about 98% of national reserves).
- MMDR Amendment 2015: Provided greater transparency in mineral allocation through auction mechanism for major minerals.
With reference to pulse production in India, consider the following statements:
- Black gram can be cultivated as both kharif and rabi crop.
- Green-gram alone accounts for nearly half of pulse production.
- In the last three decades, while the production of kharif pulses has increased, the production of rabi pulses has decreased.
Which of the statements given above is/are correct?
Detailed Explanation:
Answer: Option 1 — 1 only
This question tests knowledge about pulse cultivation patterns and production trends in India. Statement 1 is correct as black gram is a versatile pulse cultivated in both seasons, while statements 2 and 3 contain factual inaccuracies regarding production shares and trends.
✅ Statement 1 – Correct: Black gram (Urad dal) is indeed cultivated as both kharif and rabi crop in India, showing its adaptability to different seasons and agro-climatic conditions.
❌ Statement 2 – Incorrect: Green gram does not account for nearly half of pulse production; Chickpea (Chana) is the dominant pulse contributing approximately 40% of total pulse production in India.
❌ Statement 3 – Incorrect: Both kharif and rabi pulse production have increased over the last three decades due to government initiatives like National Food Security Mission and improved varieties; rabi pulses contribute over 60% of total production and have shown substantial growth.
📝 Short Notes: Pulse Production in India
| Pulse Type | Dominant Season | Share in Production | Major Producing States |
|---|---|---|---|
| Chickpea (Chana) | Rabi | ~40% | Madhya Pradesh, Rajasthan, Maharashtra |
| Pigeon Pea (Arhar/Tur) | Kharif | ~15% | Maharashtra, Karnataka, Madhya Pradesh |
| Black Gram (Urad) | Both Kharif & Rabi | ~10% | Madhya Pradesh, Rajasthan, Uttar Pradesh |
| Green Gram (Moong) | Both Kharif & Rabi | ~10% | Rajasthan, Maharashtra, Karnataka |
| Lentil (Masur) | Rabi | ~7% | Madhya Pradesh, Uttar Pradesh, West Bengal |
- Seasonal Distribution: Rabi pulses account for about 60-65% of total pulse production, while kharif pulses contribute 35-40%.
- Growth Trends: Both kharif and rabi pulse production have increased significantly since 1990s due to improved varieties, better agronomic practices, and government support schemes.
- India's Position: India is the largest producer and consumer of pulses globally, accounting for about 25% of world production.
- Key Initiatives: National Food Security Mission-Pulses (NFSM), Rashtriya Krishi Vikas Yojana (RKVY), and minimum support price (MSP) have boosted pulse production.
The crop is subtropical in nature. A hard frost is injurious to it. It requires at least 210 frost-free days and 50 to 100 centimetres of rainfall for its growth. A light well-drained soil capable of retaining moisture is ideally suited for the cultivation of the crop. Which one of the following is that crop?
Detailed Explanation:
Answer: Option 1 — Cotton
Cotton is a subtropical crop that requires at least 210 frost-free days, 50-100 cm of rainfall, and light well-drained soil capable of retaining moisture. Hard frost is highly injurious to cotton plants, making them unsuitable for cold regions. These specific climatic and soil requirements clearly distinguish cotton from other crops like jute (which requires hot humid climate), sugarcane (which needs heavy rainfall of 150-250 cm), and tea (which grows in tropical to subtropical highlands).
📝 Short Notes: Major Cash Crops and Their Growing Conditions
| Crop | Climate | Frost-Free Days | Rainfall (cm) | Soil Type |
|---|---|---|---|---|
| Cotton | Subtropical | 210+ days | 50-100 | Light, well-drained, moisture-retaining (black soil ideal) |
| Jute | Tropical (hot & humid) | Not frost-tolerant | 150-250 | Alluvial soil in deltaic regions |
| Sugarcane | Tropical/Subtropical | Frost-sensitive | 150-250 | Deep, rich loamy soil |
| Tea | Tropical to Subtropical (highlands) | Frost-sensitive | 150-250 | Well-drained acidic soil with good humus |
Among the following Tiger Reserves, which one has the largest area under “Critical Tiger Habitat”?
Detailed Explanation:
Answer: Option 3 — Nagarjunsagar-Srisailam
Nagarjunsagar-Srisailam Tiger Reserve, spread across five districts in Andhra Pradesh and Telangana, has the largest Critical Tiger Habitat (CTH) among the given options with a total area of approximately 3,728 sq. km. Critical Tiger Habitats are core areas of tiger reserves notified under the Wildlife Protection Act, 1972, which are kept inviolate for tiger conservation based on scientific evidence.
📝 Short Notes: Major Tiger Reserves and Their Critical Tiger Habitat Areas
| Tiger Reserve | State(s) | Approximate CTH Area | Notable Features |
|---|---|---|---|
| Nagarjunsagar-Srisailam | Andhra Pradesh & Telangana | ~3,728 sq. km (largest) | Spans across Krishna and Godavari basins; largest tiger reserve in India |
| Corbett | Uttarakhand | ~1,318 sq. km | India's first national park (1936); oldest tiger reserve (1973) |
| Ranthambore | Rajasthan | ~1,113 sq. km | Famous for day-time tiger sightings; historical Ranthambore Fort |
| Sundarbans | West Bengal | ~1,330 sq. km | Largest mangrove forest; UNESCO World Heritage Site; unique swimming tigers |
- Critical Tiger Habitat (CTH): Also called core areas, these are inviolate zones notified under Section 38V of the Wildlife Protection Act, 1972, where human activities are prohibited or severely restricted.
- Buffer Zones: Areas surrounding CTH where limited human activity is permitted with conservation-oriented management.
- India has 53 tiger reserves (as of 2023) covering about 75,000 sq. km across 18 states.
- Project Tiger was launched in 1973 with 9 tiger reserves; Corbett was the first.
Consider the following statements:
- Coal ash contains arsenic, lead and mercury.
- Coal-fired power plants release Sulphur dioxide and oxides of nitrogen into the environment.
- High ash content is observed in Indian coal.
Which of the statements given above is/are correct?
Detailed Explanation:
Answer: Option 4 — 1, 2 and 3
All three statements about coal combustion and Indian coal characteristics are correct. Coal ash contains heavy metals, coal-fired power plants release sulfur and nitrogen oxides, and Indian coal is characterized by high ash content.
✅ Statement 1 – Correct: Coal ash, a by-product of coal combustion, contains toxic heavy metals including arsenic, lead, and mercury, which can leach into water bodies and contaminate soil, posing environmental and health hazards.
✅ Statement 2 – Correct: Coal-fired power plants release sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) during combustion, which contribute to acid rain, respiratory issues, smog formation, and overall air pollution.
✅ Statement 3 – Correct: Indian coal, especially from eastern and central regions, has high ash content (30-50%), which reduces its calorific value, increases pollution levels, and results in large quantities of fly ash generation in thermal power plants.
📝 Short Notes: Coal Combustion and Environmental Impact
- Coal Ash Composition: Contains heavy metals (arsenic, lead, mercury, chromium, cadmium) that are toxic and carcinogenic; improper disposal can contaminate groundwater and soil.
- Air Pollutants from Coal Plants: Release SO₂ (causes acid rain), NOₓ (forms ground-level ozone and smog), particulate matter (PM2.5, PM10), CO₂ (greenhouse gas), and mercury emissions.
- Indian Coal Characteristics: High ash content (30-50% compared to 10-15% in imported coal), low calorific value (3000-4000 kcal/kg), and high moisture content.
- Fly Ash Utilization: India generates over 200 million tonnes of fly ash annually; used in cement manufacturing, brick making, road construction, and land filling.
- Environmental Regulations: MoEFCC mandates 100% fly ash utilization; thermal power plants must maintain electrostatic precipitators and FGD (Flue Gas Desulfurization) systems.
With reference to India’s Desert National Park, which of the following statements are correct?
- It is spread over two districts.
- There is no human habitation inside the Park.
- It is one of the natural habitats of Great Indian Bustard.
Select the correct answer using the code given below:
Detailed Explanation:
Answer: Option 3 — 1 and 3 only
Desert National Park is one of India's largest national parks, spread across Jaisalmer and Barmer districts of Rajasthan, representing the Thar Desert ecosystem. It is a crucial habitat for the critically endangered Great Indian Bustard, though human settlements do exist within the park boundaries.
✅ Statement 1 – Correct: The park is spread across Jaisalmer and Barmer districts of Rajasthan, covering approximately 3,162 km².
❌ Statement 2 – Incorrect: Human habitation exists within the park; several villages and communities engaged in livestock rearing are located inside.
✅ Statement 3 – Correct: It is one of the last remaining natural habitats of the critically endangered Great Indian Bustard (Ardeotis nigriceps).
📝 Short Notes: Desert National Park
- Location: Jaisalmer and Barmer districts, Rajasthan
- Area: Approximately 3,162 km², one of the largest national parks in India
- Ecosystem: Represents the Thar Desert ecosystem with sand dunes (20%), rocky terrain, salt lake bottoms, and sparse vegetation
- Key Wildlife: Great Indian Bustard (critically endangered), Chinkara, Desert Fox, Desert Cat, Wolf
- Human Presence: Unlike strict protected areas, villages and pastoral communities exist within the park
- Conservation Significance: Last stronghold for Great Indian Bustard; captive breeding programs ongoing
- Bird Diversity: Over 140 bird species recorded, including migratory and resident species
With reference to India’s biodiversity, Ceylon frogmouth, Coppersmith barbet, Gray-chinned minivet and White-throated redstart are
Detailed Explanation:
Answer: Option 1 — Birds
All four species mentioned—Ceylon frogmouth, Coppersmith barbet, Gray-chinned minivet, and White-throated redstart—are birds found in India and neighboring regions. The Ceylon frogmouth is a nocturnal bird of the Western Ghats, the Coppersmith barbet is named for its metallic call, the Gray-chinned minivet is known for its colorful plumage, and the White-throated redstart is characterized by its distinctive red tail.
📝 Short Notes: Indian Bird Species
- Ceylon Frogmouth (Batrachostomus moniliger): A nocturnal bird native to the Western Ghats and Sri Lanka; resembles a frog due to its wide mouth and camouflaged plumage; inhabits dense tropical forests.
- Coppersmith Barbet (Psilopogon haemacephalus): A resident bird across the Indian subcontinent; named for its repetitive metallic 'tuk-tuk-tuk' call resembling a coppersmith's hammer; features crimson forehead and throat with green body.
- Gray-chinned Minivet (Pericrocotus solaris): Found in the Himalayas and Southeast Asia; exhibits sexual dimorphism with males displaying orange-red plumage and females showing yellow; inhabits subtropical and temperate forests.
- White-throated Redstart (Phoenicurus schisticeps): A small passerine bird found in the Himalayas, Nepal, Bhutan, and parts of China; males have black plumage with white throat and bright rufous-red tail; prefers high-altitude scrublands and rocky areas.
- Biodiversity Significance: These species represent India's rich avian diversity across different ecological zones—from tropical forests to high-altitude regions—highlighting the importance of habitat conservation.
What is the use of biochar in farming?
- Biochar can be used as a part of the growing medium in vertical farming.
- When biochar is a part of the growing medium, it promotes the growth of nitrogen-fixing microorganisms.
- When biochar is a part of the growing medium, it enables the growing medium to retain water for longer time.
Which of the statements given above is/are correct?
Detailed Explanation:
Answer: Option 4 — 1, 2 and 3
Biochar is a carbon-rich, porous material produced through pyrolysis of biomass. It serves multiple functions in agriculture by improving soil structure, supporting beneficial microorganisms, and enhancing water retention. All three statements correctly describe the agricultural uses of biochar.
✅ Statement 1 – Correct: Biochar can be used as a component of growing media in vertical farming systems, where it improves substrate structure and nutrient retention.
✅ Statement 2 – Correct: The porous structure and chemical properties of biochar create favorable conditions for nitrogen-fixing microorganisms, enhancing biological nitrogen fixation in the soil.
✅ Statement 3 – Correct: Due to its high porosity and large surface area, biochar can absorb and retain significant amounts of water, making it available to plants over extended periods.
📝 Short Notes: Biochar in Agriculture
- Definition: Biochar is a stable, carbon-rich solid obtained from the pyrolysis (thermal decomposition in absence of oxygen) of biomass.
- Soil Amendment: Improves soil structure, porosity, and cation exchange capacity (CEC), leading to better nutrient retention.
- Water Retention: Its porous nature can hold 2-5 times its weight in water, reducing irrigation requirements.
- Microbial Habitat: Provides surface area and micro-habitats for beneficial soil microorganisms, including nitrogen-fixing bacteria.
- Carbon Sequestration: Stores carbon in soil for hundreds to thousands of years, contributing to climate change mitigation.
- Nutrient Management: Reduces nutrient leaching, improves fertilizer efficiency, and can adsorb contaminants.
- Applications: Used in conventional farming, vertical farming, container gardening, and soil remediation projects.
In rural road construction, the use of which of the following is preferred for ensuring environmental sustainability or to reduce carbon footprint?
- Copper slag
- Cold mix asphalt technology
- Geotextiles
- Hot mix asphalt technology
- Portlant cement
Select the correct answer using the code given below:
Detailed Explanation:
Answer: Option 1 — 1, 2 and 3 only
For ensuring environmental sustainability and reducing carbon footprint in rural road construction, copper slag (a by-product reducing natural resource demand), cold mix asphalt (lower temperature processing with reduced emissions), and geotextiles (synthetic materials minimizing excavation and resource use) are preferred. Hot mix asphalt requires high energy consumption, and Portland cement production is carbon-intensive, making them less environmentally sustainable choices.
✅ Statement 1 – Correct: Copper slag, a copper refining by-product, can replace sand in concrete, reducing sand mining and environmental impact.
✅ Statement 2 – Correct: Cold mix asphalt technology operates at lower temperatures, consuming less energy and emitting fewer greenhouse gases compared to hot mix.
✅ Statement 3 – Correct: Geotextiles provide soil stabilization and drainage while reducing the need for excessive excavation and natural resource consumption.
❌ Statement 4 – Incorrect: Hot mix asphalt technology requires high temperatures and thus higher energy consumption, making it less environmentally sustainable.
❌ Statement 5 – Incorrect: Portland cement production is highly energy-intensive and emits significant CO₂, contributing substantially to carbon footprint.
📝 Short Notes: Sustainable Road Construction Materials
| Material/Technology | Environmental Benefits | Carbon Footprint Impact |
|---|---|---|
| Copper Slag | By-product utilization; reduces sand mining; waste recycling | Low - diverts industrial waste |
| Cold Mix Asphalt | Lower production temperature (60-100°C vs 150-180°C); allows recycled materials; can be produced on-site | Reduced by 30-50% compared to hot mix |
| Geotextiles | Reduces excavation depth; improves soil stability; extends road life; reduces gravel/stone requirement | Low - reduces material transport and extraction |
| Hot Mix Asphalt | Good performance but high energy demand | High - requires 150-180°C processing |
| Portland Cement | Limited - energy-intensive production | Very High - 0.8-0.9 kg CO₂ per kg cement |
- Green Road Construction: Focus on using industrial by-products, recycled materials, and low-energy technologies
- Rural Road Context: PMGSY (Pradhan Mantri Gram Sadak Yojana) encourages use of sustainable materials and local resources
- Geotextiles Applications: Separation, filtration, drainage, reinforcement, and erosion control in road construction
- Fly Ash & Slag: Other industrial by-products increasingly used as sustainable alternatives in road construction
Which of the following are the most likely places to find the musk deer in its natural habitat?
- Askot Wildlife Sanctuary
- Gangotri National Park
- Kishanpur Wildlife Sanctuary
- Manas National Park
Select the correct answer using the code given below:
Detailed Explanation:
Answer: Option 1 — 1 and 2 only
Musk deer are found in high-altitude Himalayan regions, typically above 2,500 meters. Askot Wildlife Sanctuary and Gangotri National Park, both located in Uttarakhand's Himalayan ranges, provide the ideal alpine and subalpine habitat for musk deer. Kishanpur Wildlife Sanctuary consists of terai grasslands unsuitable for musk deer, while Manas National Park in Assam is a lowland tropical forest ecosystem that does not support musk deer populations.
✅ Statement 1 – Correct: Askot Wildlife Sanctuary in Uttarakhand is specifically known for musk deer conservation in high-altitude Himalayan habitat.
✅ Statement 2 – Correct: Gangotri National Park in Uttarakhand is a high-altitude region where musk deer are naturally found.
❌ Statement 3 – Incorrect: Kishanpur Wildlife Sanctuary in Uttar Pradesh has terai grasslands, not the high-altitude habitat required by musk deer.
❌ Statement 4 – Incorrect: Manas National Park in Assam is a lowland tropical forest unsuitable for musk deer which require alpine habitats.
📝 Short Notes: Musk Deer
- Scientific Name: Moschus species (Himalayan Musk Deer - Moschus leucogaster)
- Habitat: High-altitude Himalayan forests (2,500-4,500 m), alpine meadows, and scrub zones
- Distribution in India: Uttarakhand, Himachal Pradesh, Jammu & Kashmir, Sikkim, and Arunachal Pradesh
- Conservation Status: Endangered (IUCN); Schedule I (Wildlife Protection Act, 1972)
- Key Feature: Males possess musk gland (pod) that produces valuable musk, leading to illegal poaching
- Protected Areas: Askot Wildlife Sanctuary, Gangotri National Park, Kedarnath Wildlife Sanctuary, Great Himalayan National Park, Nanda Devi National Park
- Threats: Habitat loss, poaching for musk, climate change affecting alpine habitats
With reference to Indian elephants, consider the following statements:
- The leader of an elephant group is a female.
- The maximum gestation period can be 22 months.
- An elephant can normally go on calving till the age of 40 years only.
- Among the States in India, the highest elephant population is in Kerala.
Which of the statements given above is/are correct?
Detailed Explanation:
Answer: Option 1 — 1 and 2 only
Indian elephants live in matriarchal societies where the oldest and most experienced female leads the herd, while males typically live solitary lives or form bachelor groups. The gestation period of elephants is the longest among land mammals, ranging from 18 to 22 months.
✅ Statement 1 – Correct: Elephant herds are matriarchal, led by the oldest and most experienced female (matriarch), while adult males usually live alone or in bachelor groups.
✅ Statement 2 – Correct: Elephants have the longest gestation period among mammals, ranging from 18 to 22 months, with an average of about 22 months.
❌ Statement 3 – Incorrect: Female elephants can continue to reproduce well beyond 40 years of age, often calving into their 50s and sometimes even early 60s, though fertility may decline with age.
❌ Statement 4 – Incorrect: Karnataka has the highest elephant population in India (around 6,000), followed by Assam and Kerala. Kerala ranks third, not first.
📝 Short Notes: Indian Elephants
- Scientific Name: Elephas maximus indicus (subspecies of Asian elephant)
- Protection Status: Schedule I of Wildlife Protection Act, 1972; Appendix I of CITES; IUCN Red List - Endangered
- Social Structure: Matriarchal herds of 6-12 individuals led by the oldest female; adult males are solitary or form temporary bachelor groups
- Reproduction: Gestation period 18-22 months (longest among mammals); females reach sexual maturity at 10-12 years; can reproduce until 50-60 years of age; typically give birth to one calf every 4-5 years
- Distribution in India: Karnataka (highest population ~6,000), Assam (~5,700), Kerala (~3,000), Tamil Nadu, and northeastern states
- Project Elephant: Launched in 1992 to protect elephants, their habitats, and migration corridors; 33 elephant reserves established across 16 states
- Major Threats: Habitat loss and fragmentation, human-elephant conflict, poaching for ivory (though Indian elephants have smaller tusks than African elephants), railway and road accidents
UPSC Prelims 2020 Questions Paper - Subject-wise Question Distribution
UPSC Prelims 2020 Question Paper - FAQs & Analysis
Q1 How many total questions were asked in UPSC Prelims 2020?
Q2 What is the subject-wise question breakdown for UPSC Prelims 2020?
- Indian Economy: 23 questions (23%)
- Environment & Ecology: 19 questions (19%)
- Indian Polity: 17 questions (17%)
- Science & Technology: 13 questions (13%)
- Modern History: 9 questions (9%)
- Ancient History: 8 questions (8%)
- World Geography: 4 questions (4%)
- International Relations: 3 questions (3%)
- Indian Geography: 2 questions (2%)
- Medieval History: 2 questions (2%)