UPSC Prelims PYQs with explanations
Real questions from official papers, mapped to syllabus topics. Attempt each one; the answer and the reason appear instantly.
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?
Answer (d) & explanation
All three statements are correct (d). Statement 1 is right: Climate-Smart Villages in Haryana, Punjab, Bihar and other States were set up under CCAFS (Climate Change, Agriculture and Food Security), an international research programme. They test farm practices that adapt to climate change and cut emissions. Statement 2 is right: CCAFS ran under the CGIAR, whose system office is in Montpellier, France. Statement 3 is right: ICRISAT at Patancheru, Hyderabad, is one of the CGIAR research centres.
Notice other CGIAR centres: IRRI (Philippines, rice), CIMMYT (Mexico, maize and wheat) and IWMI (Sri Lanka). India's own programme is NICRA (National Innovations in Climate Resilient Agriculture) of the ICAR.
Answer as per the official UPSC answer key.
Constitutional government means
Answer (d) & explanation
Constitutional government means a government limited by the Constitution (d). A constitutional government is a limited government: its powers are bound by a higher law that it cannot override at will, with rights for citizens and checks such as judicial review. It may be federal or unitary, and parliamentary or presidential. Option (a) is wrong: a federal structure is not required. Options (b) and (c) are wrong: whether the head has nominal or real powers decides parliamentary versus presidential, not whether the government is constitutional.
Notice the idea of constitutionalism: the limits on power, not just the existence of a written text. A dictatorship may have a written constitution and still not be a constitutional government. Britain has constitutionalism without a single written constitution.
Answer as per the official UPSC answer key.
A woman runs 12 km towards her North, then 6 km towards her South and then 8 km towards her East. In which direction is she from her starting point ?
Answer (b) & explanation
She is at an angle less than 45° North of East (b). Step 1: 12 km North, then 6 km South, leaves her 6 km North. Then 8 km East. Step 2: so her net position is 6 km North and 8 km East. Step 3: the north part (6) is less than the east part (8). So the direction is closer to East: tan θ = 6/8, giving about 37° North of East, less than 45°. Options (a) and (c) wrongly say South. Option (d) says more than 45°.
Tip: if the two parts are equal, the angle is exactly 45°. The bigger part decides which direction the line leans towards.
Answer as per the official UPSC answer key.
Read the passage
Our cities are extremely vulnerable to climate change because of large concentrations of populations and poor infrastructure. Moreover, population densities are increasing in them but we have not yet developed the systems to address climate change impacts. Our cities contribute to 65 per cent of the GDP, but there are not enough facilities to cater to the needs of the people. It is important to address the issues of air quality, transport, etc., that are vital to identifying sustainable solutions. We need to involve citizens in city planning and create an ecosystem that meets the needs of the people.
Which among the following is the most logical and rational inference that can be made from the passage given above ?
Answer (c) & explanation
The best inference is that our cities need sustainability-related interventions to be maintained and developed (c). Step 1: the passage says cities are vulnerable to climate change. It says air quality, transport and citizen planning are "vital to identifying sustainable solutions". That is (c). Step 2: option (a), administrative autonomy, and option (d), PPP mode, are never mentioned. Step 3: option (b) calls rising density a hindrance to sustainable development. The passage mentions density only as one cause of vulnerability; it does not make it the main barrier.
Tip: pick the option that uses the passage's own keywords and conclusion. Options naming specific models (PPP, autonomy) are usually outside the text.
Answer as per the official UPSC answer key.
Consider the following statements :
Other things remaining unchanged, market demand for a good might increase if
- 1. price of its substitute increases
- 2. price of its complement increases
- 3. the good is an inferior good and income of the consumers increases
- 4. its price falls
Which of the above statements are correct?
Answer (a) & explanation
Statements 1 and 4 are correct (a). Statement 1 is right: if a substitute gets dearer, people switch to this good. If tea costs more, demand for coffee rises. Statement 2 is wrong: if a complement gets dearer, demand falls. If petrol costs more, people buy fewer cars. Statement 3 is wrong: for an inferior good, such as coarse grain, demand falls as income rises, because people switch to better goods. Statement 4 is right: by the law of demand, a fall in a good's own price raises the quantity demanded.
Notice the exceptions to the law of demand: Giffen goods and Veblen goods (luxury status goods). Also note the difference between a movement along the demand curve (own price) and a shift of the curve (other factors).
Answer as per the official UPSC answer key.
With reference to Madanapalle of Andhra Pradesh, which one of the following statements is correct?
Answer (c) & explanation
Tagore translated the National Anthem into English at Madanapalle (c). In February 1919, Rabindranath Tagore stayed at Besant Theosophical College, Madanapalle, with its principal, the Irish poet James Cousins. There he translated Jana Gana Mana into English as "The Morning Song of India", and Cousins's wife Margaret set the tune. Option (a) is wrong: Pingali Venkayya designed the flag but not at Madanapalle. Option (b) is wrong: Pattabhi Sitaramaiah was linked to Machilipatnam. Option (d) is wrong: the Theosophical Society started in New York (1875) and moved to Adyar, Madras, in 1882.
Notice that Jana Gana Mana was first sung at the Congress session in Calcutta in 1911, and adopted as the anthem on 24 January 1950.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. Adenoviruses have single-stranded DNA genomes whereas retroviruses have double-stranded DNA genomes.
- 2. Common cold is sometime caused by an adenovirus whereas AIDS is caused by a retrovirus.
Which of the statements given above is/are correct?
Answer (b) & explanation
Only statement 2 is correct (b). Statement 1 is wrong on both counts. Adenoviruses have double-stranded DNA genomes. Retroviruses, such as HIV, carry single-stranded RNA, which an enzyme called reverse transcriptase copies into DNA that joins the host's genome. Statement 2 is right: adenoviruses cause some common colds, sore throats and conjunctivitis, while HIV, a retrovirus, causes AIDS.
Notice that most colds are caused by rhinoviruses, with adenoviruses and coronaviruses behind some. Adenoviruses are also used as vectors in vaccines such as Covishield. HIV treatment uses antiretroviral therapy (ART), and India's National AIDS Control Programme began in 1992.
Answer as per the official UPSC answer key.
With reference to 8th August, 1942 in Indian history, which one of the following statements is correct?
Answer (a) & explanation
The AICC adopted the Quit India Resolution (a). On 8 August 1942, the All India Congress Committee passed the Quit India resolution at Gowalia Tank, Bombay, and Gandhi gave the call "Do or Die". The top leaders were arrested early on 9 August, now marked as August Kranti Diwas. Option (b) is wrong: the Viceroy's Executive Council was expanded in 1941 under the August Offer. Option (c) is wrong: the Congress ministries resigned in October–November 1939. Option (d) is wrong: Cripps came in March 1942.
Notice Aruna Asaf Ali, who hoisted the flag at Gowalia Tank, and Usha Mehta, who ran the secret Congress Radio. Parallel governments were set up at Ballia, Tamluk and Satara.
Answer as per the official UPSC answer key.
Read the passage
With respect to what are called denominations of religion, if everyone is left to be a judge of his own religion, there is no such thing as religion that is wrong; but if they are to be a judge of each other’s religion, there is no such thing as a religion that is right, and therefore all the world is right or all the world is wrong in the matter of religion.
What is the most logical assumption that can be made from the passage given above ?
Answer (c) & explanation
The most logical assumption is that religious denominations tend to ignore the unity of man (c). Step 1: the passage says if each judges his own religion, all are right. But if each judges the others', none is right. Each group sees only its own view, so they divide people instead of seeing what they share. That is (c). Step 2: option (a) says no one can live without a religion; the passage does not say this. Option (b), a duty to spread one's religion, is also not stated. Step 3: option (d) says men do not understand their own religion; the passage never doubts that.
Tip: an assumption must sit underneath the author's argument. Reject options that bring in duties or needs the passage never mentions.
Answer as per the official UPSC answer key.
There are three points P, Q and R on a straight line such that PQ : QR = 3 : 5. If n is the number of possible values of PQ : PR, then what is n equal to ?
Answer (b) & explanation
There are 2 possible values of PQ : PR (b). Step 1: take PQ = 3 and QR = 5. Draw the possible orders. Step 2: if Q lies between P and R, then PR = 3 + 5 = 8, giving 3 : 8. If P lies between Q and R, then PR = 5 − 3 = 2, giving 3 : 2. Step 3: R cannot lie between P and Q, because QR (5) is longer than PQ (3). So n = 2. Options (a), (c) and (d) miscount the cases.
Tip: for points on a line, list every possible order and test each one. A case is possible only if the lengths fit.
Answer as per the official UPSC answer key.
In India, the central bank's function as the 'lender of last resort' usually refers to which of the following?
- 1. Lending to trade and industry bodies when they fail to borrow from other sources
- 2. Providing liquidity to the banks having a temporary crisis
- 3. Lending to governments to finance budgetary deficits
Select the correct answer using the code given below.
Answer (b) & explanation
Only statement 2 describes the lender of last resort (b). As lender of last resort, the RBI gives emergency funds to a basically sound bank that faces a sudden shortage of cash, so that panic does not spread to other banks and the system stays stable. The Marginal Standing Facility is one such window. Statement 1 is wrong: the RBI does not lend directly to trade or industry bodies. Statement 3 is wrong: lending to governments through ways and means advances is its role as banker to the government, not as lender of last resort.
Notice the idea came from Walter Bagehot's Lombard Street (1873): lend freely to solvent banks, against good collateral, at a penalty rate.
Answer as per the official UPSC answer key.
Which one of the following statements is correct?
Answer (a) & explanation
Ajanta lies in the gorge of the Waghora river (a). The Ajanta caves, near Aurangabad in Maharashtra, are cut into a horseshoe-shaped cliff above the Waghora river. There are about 30 Buddhist caves, from the 2nd century BC to the 5th century AD, famous for murals. Option (b) is wrong: Sanchi stands on a hill near Vidisha in the Betwa valley. Option (c) is wrong: Pandu-lena caves are on a hill at Nashik, near the Godavari. Option (d) is wrong: Amaravati stands on the Krishna, not in a gorge.
Notice that much of Ajanta's later work was under the Vakataka king Harishena. Ajanta was rediscovered by a British officer, John Smith, in 1819.
Answer as per the official UPSC answer key.
Consider the following statements :
- 1. 'Right to the City' is an agreed human right and the UN-Habitat monitors the commitments made by each country in this regard.
- 2. 'Right to the City' gives every occupant of the city the right to reclaim public spaces and public participation in the city.
- 3. 'Right to the City' means that the State cannot deny any public service or facility to the unauthorized colonies in the city.
Which of the statements given above is/are correct?
Answer (d) & explanation
Statements 2 and 3 are correct (d). The "Right to the City" is an idea from the French thinker Henri Lefebvre (1968). Statement 1 is wrong: it was taken up in the UN's New Urban Agenda (Habitat III, Quito, 2016), but it is not a binding, agreed human right that UN-Habitat monitors country by country. Statement 2 is right: it covers every resident's claim to reclaim public spaces and take part in city decisions. Statement 3 is right: it means the State cannot deny basic services to people in unauthorised colonies.
Notice India's urban schemes: PMAY-Urban, AMRUT and the Smart Cities Mission. The 74th Amendment (1992) gave constitutional status to urban local bodies.
"agreed human right" and "monitors" turn a policy idea into a treaty. Words like these usually signal a wrong statement.
Answer as per the official UPSC answer key.
A Statement followed by Conclusion-I and Conclusion-II is given below. You have to take the Statement to be true even if it seems to be at variance from the commonly known facts. Read all Conclusions and then decide which of the given Conclusion(s) logically follows/follow from the Statement, disregarding the commonly known facts.
Statement : Some radios are mobiles. All mobiles are computers. Some computers are watches.
Conclusion-I : Certainly some radios are watches.
Conclusion-II : Certainly some mobiles are watches.
Which one of the following is correct ?
Answer (d) & explanation
Neither conclusion follows (d). Step 1: some radios are mobiles, and all mobiles are computers. The watches are linked only to "some computers". Step 2: those computers may be ones that are not mobiles and not radios. So we cannot be sure any radio or mobile is a watch. Step 3: conclusions I and II both say "certainly", so neither follows. Options (a), (b) and (c) fail.
Tip: "some A are B" and "some B are C" give no sure link between A and C. Draw the circles so that the watches touch computers away from mobiles. If such a drawing is possible, the "certain" conclusion fails.
The word 'certainly' needs a sure link; a 'some' link through a big group (computers) is not sure.
Answer as per the official UPSC answer key.
Read the passage
In the immediate future, we will see the increasing commodification of many new technologies — artificial intelligence and robotics, 3D manufacturing, custom made biological and pharmaceutical products, lethal autonomous weapons and driverless cars. This will pose conundrums. The moral question of how a driverless car will decide between hitting a jaywalker and swerving and damaging the car has often been debated. The answer is both simple — save the human life — and complex. At which angle should the car swerve — just enough to save the jaywalker or more than enough ? If the driverless car is in Dublin, who would take the decision ? The Irish Government, or the car’s original code writer in California, or a software programmer in Hyderabad to whom maintenance is outsourced ? If different national jurisdictions have different fine print on prioritising a human life, how will it affect insurance and investment decisions, including transnational ones ?
Which of the following statements best reflect the rational, plausible and practical implications that can be derived from the passage given above ?
- 1. Too much globalization is not in the best interests of any country.
- 2. Modern technologies are increasingly blurring the economic borders.
- 3. Innovation and capital have impinged on the domain of the State.
- 4. Public policy of every country should focus on developing its own supply chains.
- 5. Geopolitics will have to reconcile to many ambiguities and uncertainties.
Select the correct answer using the code given below :
Answer (c) & explanation
Implications 2, 3 and 5 are valid (c). Step 1: one driverless car involves Dublin, a code writer in California and a programmer in Hyderabad. Technology is blurring economic borders (2). Step 2: a code writer, not a government, may decide how the car swerves. Innovation and capital have entered the domain of the state (3). Step 3: different countries have different rules, which creates uncertainty for geopolitics, insurance and investment (5). Statements 1 (too much globalisation is bad) and 4 (build your own supply chains) are policy opinions the passage never gives. So options (a), (b) and (d) fail.
Tip: an implication follows from facts in the passage. Advice about what countries "should" do needs the author to argue it.
Answer as per the official UPSC answer key.
A pie diagram shows the percentage distribution of proteins, water and other dry elements in the human body. Given that proteins correspond to 16% and water corresponds to 70%. If both proteins and the other dry elements correspond to p%, then what is the central angle of the sector representing p on the pie diagram ?
Answer (c) & explanation
The central angle is 108° (c). Step 1: proteins are 16% and water is 70%. Everything else is the "other dry elements". Step 2: p% is proteins plus other dry elements, which is everything except water: 100 − 70 = 30%. Step 3: a full pie is 360°. So 30% of 360° = 108°. Option (a), 54°, uses only part of it. Options (b) and (d) use wrong percentages.
Tip: in a pie chart, 1% = 3.6°. Often the quickest route is to subtract the parts you don't need from 100%.
Answer as per the official UPSC answer key.
Which one of the following is a filter feeder?
Answer (c) & explanation
The oyster is a filter feeder (c). An oyster pumps water through its gills and strains out plankton and fine organic particles, so it is a filter feeder. One adult oyster can filter many litres of water an hour, which also cleans the water and makes oyster reefs valuable to coastal ecosystems. Option (a) is wrong: a catfish is a bottom feeder and scavenger that eats insects, fish and debris. Option (b) is wrong: an octopus is a predator that catches crabs and fish. Option (d) is wrong: a pelican scoops up fish in its throat pouch; it drains the water but does not filter food.
Notice other filter feeders: clams, mussels, sponges, barnacles, flamingos, and the baleen whales and whale shark.
Answer as per the official UPSC answer key.
“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
Answer (d) & explanation
This describes the tropical rain forest (d). Leaf litter decays fastest where heat and moisture are constant all year: the tropical rain forest. Microbes, fungi and insects break down fallen leaves within weeks, so the soil surface is often almost bare. Little light reaches the floor, so many plants climb (lianas) or grow on branches (epiphytes, such as orchids and ferns) to reach the canopy. Coniferous forests (a) are cold, so litter decays slowly. Dry deciduous forests (b) have a long dry season. Mangroves (c) are coastal and waterlogged.
Notice that rain forest soils are poor, because nutrients are quickly taken up by plants and washed out by rain. India's rain forests are in the Western Ghats, the North-East and the Andamans.
Answer as per the official UPSC answer key.
With reference to India, the terms ‘Halbi, Ho and Kui’ pertain to
Answer (d) & explanation
Halbi, Ho and Kui are tribal languages (d). Halbi is an Indo-Aryan language spoken in Bastar (Chhattisgarh) and nearby areas. Ho is a Munda (Austroasiatic) language of Jharkhand and Odisha, with its own Warang Chiti script. Kui is a Dravidian language of the Kandha (Khond) people in Odisha. They are not dance forms (a), musical instruments (b) or cave paintings (c).
Notice the Eighth Schedule, which lists 22 languages; tribal languages in it are Santali (with its Ol Chiki script) and Bodo, added by the 92nd Amendment (2003). Demands remain to add Ho, Mundari and Kurukh. Notice the four language families of India: Indo-Aryan, Dravidian, Austroasiatic and Tibeto-Burman.
Answer as per the official UPSC answer key.
Read the passage
India faces a challenging immediate future in energy and climate policy-making. The problems are multiple : sputtering fossil fuel production capabilities; limited access to electricity and modern cooking fuel for the poorest; rising fuel imports in an unstable global energy context; continued electricity pricing and governance challenges leading to its costly deficits or surplus supply; and not least, growing environmental contestation around land, water and air. But all is not bleak: growing energy efficiency programmes; integrated urbanisation and transport policy discussions; inroads to enhancing energy access and security; and bold renewable energy initiatives, even if not fully conceptualised, suggest the promise of transformation.
Which one of the following statements best reflects the critical message conveyed by the passage given above ?
Answer (a) & explanation
The critical message is that India's energy decisions are becoming more complex and interlinked (a). Step 1: the passage lists many linked problems: supply, access, imports, pricing and environment. It also lists linked responses. So decision-making is complex. That is (a). Step 2: options (c) and (d) are too negative. The passage speaks of a "promise of transformation", not failure or a narrow supply focus. Step 3: option (b), policy heavily tuned to sustainable development goals, overstates what the passage says.
Tip: if a passage piles up many connected issues, the message is usually "complexity". Check the passage's tone before choosing a negative option.
Answer as per the official UPSC answer key.