UPSC Prelims 2013 Question Paper
Explore the complete solved question paper for UPSC Prelims 2013 featuring 100 solved questions with bilingual (English & Hindi) explanations, official answer key, and subject weightage breakdown.
Which of the following adds/add nitrogen to the soil?
- Excretion of urea by animals
- Burning of coal by man
- Death of vegetation
Select the correct answer using the codes given below.
Detailed Explanation:
✅ Statement 1 – Correct: Urea (CO(NH₂)₂) excreted by animals is decomposed by soil microbes into ammonia, which is further converted into nitrates and nitrites, adding nitrogen to soil.
❌ Statement 2 – Incorrect: Burning of coal releases nitrogen oxides (NOₓ) into the atmosphere, not directly into soil; these contribute to air pollution and acid rain.
✅ Statement 3 – Correct: Death of vegetation leads to decomposition by bacteria and fungi, which breaks down organic matter and releases nitrogen compounds back into soil.
Due to improper/indiscriminate disposal of old and used computers or their parts, which of the following are released into the environment as e-waste?
- Beryllium
- Cadmium
- Chromium
- Heptachlor
- Mercury
- Lead
- Plutonium
Select the correct answer using the codes given below.
Detailed Explanation:
E-waste from computers contains heavy metals used in electronic components: Beryllium (motherboards, connectors), Cadmium (rechargeable batteries, circuit boards), Chromium (corrosion protection in steel plates), Mercury (fluorescent lamps, switches), and Lead (solder, CRT monitors).
Heptachlor is an organochlorine insecticide, not used in electronics, and Plutonium is a radioactive element found only in nuclear applications, not in computers.
Which one of the following terms describes not only the physical space occupied by an organism but also its functional role in the community of organisms?
Detailed Explanation:
Ecological niche describes both the physical space occupied by an organism and its functional role in the community, including its interactions with biotic and abiotic factors.
Habitat refers only to the physical location where an organism lives, while ecotone is a transition zone between two ecosystems, and home range is the area an animal travels during normal activities.
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In which of the following States is lion-tailed macaque found in its natural habitat?
- Tamil Nadu
- Kerala
- Karnataka
- Andhra Pradesh
Select the correct answer using the codes given below.
Detailed Explanation:
✅ Statement 1 – Correct: Lion-tailed macaque is found in Tamil Nadu's Western Ghats forests, particularly in Anaimalai Hills and surrounding evergreen regions.
✅ Statement 2 – Correct: Kerala hosts significant populations in Silent Valley National Park and other Western Ghats rainforests.
✅ Statement 3 – Correct: Karnataka's Western Ghats regions including Kudremukh and Sirsi-Honnavara ranges form part of the natural habitat.
❌ Statement 4 – Incorrect: Andhra Pradesh lies outside the Western Ghats endemic zone; the species is not found naturally in this state.
Which one of the following is the correct sequence of ecosystems in the order of decreasing productivity?
Detailed Explanation:
Ecosystems ranked by Net Primary Productivity (NPP) from highest to lowest:
Mangroves (high NPP) – receive nutrient inputs from both terrestrial runoff and tidal flushing, warm tropical climate, high photosynthetic rates
Grasslands (moderate NPP) – abundant herbaceous vegetation with productivity dependent on rainfall, soil fertility, and grazing intensity
Lakes (moderate to low NPP) – productivity varies with nutrient status (eutrophic > oligotrophic), generally lower than terrestrial ecosystems
Oceans (lowest NPP) – particularly open ocean zones have limited nutrient availability in photic zones, lowest productivity despite covering largest area
Consider the following organisms:
- Agaricus
- Nostoc
- Spirogyra
Which of the above is/are used as biofertilizer/biofertilizers?
Detailed Explanation:
Nostoc is a nitrogen-fixing cyanobacterium (blue-green algae) used as a biofertilizer due to its ability to fix atmospheric nitrogen and enrich soil.
Agaricus is a mushroom (fungus) used for food, not as a biofertilizer.
Spirogyra is a green alga (filamentous) used for research and education, not as a biofertilizer.
Consider the following pairs about parks and rivers passing through them:
- Corbett National Park: Ganga
- Kaziranga National Park: Manas
- Silent Valley National Park: Kaveri
Which of the above pairs is/are correctly matched?
Detailed Explanation:
❌ Pair 1 – Incorrect: Ramganga River (not Ganga) flows through Corbett National Park, Uttarakhand.
❌ Pair 2 – Incorrect: Brahmaputra River (not Manas) flows through Kaziranga National Park, Assam. Manas is a separate river flowing through Manas National Park.
❌ Pair 3 – Incorrect: Kunthipuzha River (not Kaveri) flows through Silent Valley National Park, Kerala.
Consider the following:
- Star tortoise
- Monitor lizard
- Pygmy Hog
- Spider monkey
Which of the above are found in India?
Detailed Explanation:
✅ Star Tortoise – Found in India: Native to dry scrub forests of south and west India, listed as Vulnerable on IUCN Red List.
✅ Monitor Lizard – Found in India: Four species (Bengal Monitor, Water Monitor, Desert Monitor, Yellow Monitor) protected under Schedule I of Wildlife Protection Act, 1972.
✅ Pygmy Hog – Found in India: World's smallest and rarest wild pig, now restricted to Manas National Park, Assam, listed as Critically Endangered.
❌ Spider Monkey – Not Found in India: New World monkey native to Central and South America (southern Mexico to Brazil), absent from Indian wildlife.
Consider the following pairs:
| Protected areas | Region |
|---|---|
| 1. Nokrek Biosphere Reserve | Garo Hills |
| 2. Logtak (Loktak) Lake | Barail Range |
| 3. Namdapha National Park | Dafla Hills |
Which of the above pairs is/are correctly matched?
Detailed Explanation:
✅ Pair 1 – Correct: Nokrek Biosphere Reserve is located in the Garo Hills of Meghalaya, known for conserving citrus gene pool.
❌ Pair 2 – Incorrect: Loktak Lake is located in Manipur valley (not Barail Range), famous for Keibul Lamjao National Park with floating phumdis.
❌ Pair 3 – Incorrect: Namdapha National Park is in Changlang district of Arunachal Pradesh near Myanmar border (not in Dafla Hills, which are in central Arunachal).
Consider the following fauna of India:
- Gharial
- Leatherback turtle
- Swamp deer
Which of the above is/are endangered?
Detailed Explanation:
✅ Gharial (Gavialis gangeticus) – Listed as Critically Endangered (CR) on IUCN Red List; faces drastic population decline due to habitat loss, prey depletion, and fishing nets.
✅ Leatherback turtle (Dermochelys coriacea) – Categorized as Vulnerable (VU) globally; found in Andaman & Nicobar Islands; protected under Schedule I, Wildlife Protection Act, 1972.
✅ Swamp deer/Barasingha (Rucervus duvaucelii) – Listed as Vulnerable (VU) on IUCN Red List; threatened by habitat fragmentation and grassland conversion.
All three species fall under IUCN 'Threatened' categories (CR/EN/VU) and are considered endangered in broader conservation context.
Contour bunding is a method of soil conservation used in
Detailed Explanation:
Contour bunding is a soil and water conservation technique used on sloping lands (typically 2-10% gradient) where earthen embankments are constructed along contour lines to reduce water runoff velocity and prevent soil erosion.
It is primarily employed in rainfed agricultural areas on gentle to moderate slopes, not in desert margins (where wind breaks are used), flat plains (where leveling/drainage is needed), or scrublands (where weed control is unrelated to contour structures).
Which one among the following industries is the maximum consumer of water in India?
Detailed Explanation:
Thermal power plants are the maximum consumers of industrial water in India, accounting for approximately 88% of annual industrial water consumption.
Engineering (~5%), Paper & Pulp (~2.3%), and Textiles (~2%) industries consume significantly smaller shares of industrial water, making thermal power the clear frontrunner in industrial water usage.
Which of the following leaf modifications occurs/occur in desert areas to inhibit water loss?
- Hard and waxy leaves
- Tiny leaves or no leaves
- Thorns instead of leaves
Select the correct answer using the codes given below.
Detailed Explanation:
✅ Statement 1 – Correct: Desert plants develop hard, waxy cuticles on leaves to create a waterproof barrier that prevents transpiration and water loss.
✅ Statement 2 – Correct: Reduced leaf size or complete leaf loss minimizes surface area exposed to heat and sunlight, thereby reducing water evaporation.
✅ Statement 3 – Correct: Leaf modification into thorns/spines drastically reduces transpiring surface area while providing protection from herbivores in arid environments.
Economic growth in country X will necessarily have to occur if
Detailed Explanation:
Capital formation is the only factor among the given options that necessarily leads to economic growth within a country.
✅ Statement 3 – Correct: Capital formation in X (investment in physical capital like machinery, infrastructure, and human capital) directly increases the productive capacity of the economy, making growth inevitable.
❌ Statement 1 – Incorrect: Technical progress in the world economy does not guarantee growth in country X unless X adopts and implements those technologies.
❌ Statement 2 – Incorrect: Population growth in X alone does not ensure economic growth; it may even lower per capita income if not accompanied by proportionate increase in production.
❌ Statement 4 – Incorrect: Growth in world trade volume benefits country X only if it actively participates and increases its share; mere global trade expansion is insufficient.
Disguised unemployment generally means
Detailed Explanation:
Disguised unemployment occurs when more people are engaged in work than actually required, typically seen in agriculture where entire families work on small plots.
The key characteristic is that removal of surplus workers would not reduce total output, meaning their marginal productivity is zero.
A rise in the general level of prices may be caused by:
- an increase in the money supply
- a decrease in the aggregate level of output
- an increase in the effective demand
Select the correct answer using the codes given below.
Detailed Explanation:
✅ Statement 1 – Correct: An increase in money supply without corresponding increase in output leads to more money chasing fewer goods, causing demand-pull inflation as per the Quantity Theory of Money.
✅ Statement 2 – Correct: A decrease in aggregate output/supply while demand remains constant creates excess demand, pushing prices upward through supply-side inflation.
✅ Statement 3 – Correct: An increase in effective demand (purchasing power-backed demand) beyond the economy's productive capacity causes demand-pull inflation.
Supply of money remaining the same when there is an increase in demand for money, there will be:
Detailed Explanation:
When money supply is constant and demand for money increases, there is greater competition for the available money in the economy.
According to the Liquidity Preference Theory, banks and lenders respond by raising the interest rate to equilibrate the money market—higher rates reduce money demand and attract more deposits, restoring balance between supply and demand.
The balance of payments of a country is a systematic record of
Detailed Explanation:
Balance of Payments (BoP) is a systematic record of all economic transactions between residents of a country and the rest of the world during a specific period (usually a year).
It includes trade in goods (visible trade), trade in services (invisible trade), income flows, current transfers, and capital and financial account transactions—making it comprehensive, not limited to just imports/exports of goods or only government transactions.
Which one of the following is likely to be the most inflationary in its effect?
Detailed Explanation:
Creating new money (Option 4) is the most inflationary method because it directly increases money supply without any corresponding increase in goods and services production, leading to demand-pull inflation.
Repayment of public debt reduces money supply; borrowing from public merely transfers existing money; borrowing from banks has moderate inflationary effect through credit creation, but printing new currency has the strongest direct impact on excess liquidity and price levels.
Consider the following statements :
- Inflation benefits the debtors.
- Inflation benefits the bondholders.
Which of the statements given above is/are correct?
Detailed Explanation:
✅ Statement 1 – Correct: Inflation erodes the real value of money. Debtors repay loans with money that has less purchasing power than when borrowed, reducing their real debt burden.
❌ Statement 2 – Incorrect: Bondholders receive fixed nominal payments. During inflation, the real value of these payments falls, causing bondholders to lose purchasing power.
UPSC Prelims 2013 Questions Paper - Subject-wise Question Distribution
UPSC Prelims 2013 Question Paper - FAQs & Analysis
Q1 How many total questions were asked in UPSC Prelims 2013?
Q2 What is the subject-wise question breakdown for UPSC Prelims 2013?
- Environment & Ecology: 21 questions (21%)
- Indian Economy: 20 questions (20%)
- Indian Polity: 17 questions (17%)
- Science & Technology: 11 questions (11%)
- World Geography: 9 questions (9%)
- Indian Art & Culture: 8 questions (8%)
- Indian Geography: 6 questions (6%)
- Modern History: 6 questions (6%)
- Ancient History: 2 questions (2%)