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 five flats, one above the other, live five professionals. The professor has to go up to meet his IAS officer friend. The doctor is equally friendly to all, and has to go up as frequently as go down. The engineer has to go up to meet his MLA friend above whose flat lives the professor's friend. From the ground floor to the top floor, in what order do the five professionals live?
Answer (d) & explanation
(d) is correct. Step 1: the doctor goes up as often as down, so he lives in the middle (3rd) flat. Step 2: the engineer goes up to meet the MLA, above whom lives the professor's friend, the IAS officer. So Engineer < MLA < IAS officer. The professor also goes up to the IAS officer, so the IAS officer is near the top. Step 3: with the doctor 3rd, MLA must be 4th and IAS 5th, leaving professor and engineer in flats 1 and 2. Only (d) fits: Professor, Engineer, Doctor, MLA, IAS officer. (a) and (c) put the IAS officer below the MLA, and (b) puts the MLA on top, so they fail.
Tip: anyone who goes up and down equally sits in the middle.
Answer as per the official UPSC answer key.
A team of scientists at Brookhaven National Laboratory including those from India created the heaviest anti-matter (anti-helium nucleus). What is/are the implication/implications of the creation of anti-matter?
- 1. It will make mineral prospecting and oil exploration easier and cheaper.
- 2. It will help probe the possibility of the existence of stars and galaxies made of anti-matter.
- 3. It will help understand the evolution of the universe.
Select the correct answer using the codes given below :
Answer (b) & explanation
Statements 2 and 3 are correct (b). The anti-helium-4 nucleus, the heaviest antimatter nucleus then made, was detected at the RHIC collider at Brookhaven (2011), with Indian scientists in the STAR team. Such work helps search for antimatter stars and galaxies (2) and understand why the early universe ended up with more matter than antimatter (3). Statement 1 is wrong: antimatter has no use in mineral or oil exploration; it is made in tiny amounts and vanishes on contact with matter. So (a), (c) and (d) fail.
Notice the related tools: the Alpha Magnetic Spectrometer on the ISS searches for cosmic antimatter. Positrons (anti-electrons) are used in medical PET scans. Trap: practical-sounding uses are attached to basic physics.
Answer as per the official UPSC answer key.
In India, other than ensuring that public funds are used efficiently and for intended purpose, what is the importance of the office of the Comptroller and Auditor General (CAG)?
- 1. CAG exercises exchequer control on behalf of the Parliament when the President of India declares national emergency/financial emergency.
- 2. CAG reports on the execution of projects or programmes by the ministries are discussed by the Public Accounts Committee.
- 3. Information from CAG reports can be used by investigating agencies to press charges against those who have violated the law while managing public finances.
- 4. While dealing with the audit and accounting of government companies, CAG has certain judicial powers for prosecuting those who violate the law.
Which of the statements given above is/are correct?
Answer (c) & explanation
Statements 2 and 3 are correct (c). CAG audit reports on ministries' projects are examined by Parliament's Public Accounts Committee, where the CAG acts as its 'friend, philosopher and guide' (2). Investigating agencies such as the CBI have used CAG findings to build cases, as in the 2G spectrum and coal block allocations (3). Statement 1 is wrong: India's CAG has no exchequer control, even in an emergency; that is a power of Britain's Comptroller. Statement 4 is wrong: the CAG has no judicial or prosecuting powers. So (a), (b) and (d) fail.
Notice the basics: CAG is appointed under Article 148, holds office for six years or until 65, is removable like a Supreme Court judge, and reports go through the President (Article 151). Trap: 'Comptroller' in the title suggests control it does not have.
Answer as per the official UPSC answer key.
Consider the following protected areas :
- 1. Bandipur
- 2. Bhitarkanika
- 3. Manas
- 4. Sunderbans
Which of the above are declared Tiger Reserves?
Answer (b) & explanation
Bandipur, Manas and Sundarbans are correct (b). Bandipur (Karnataka), Manas (Assam) and Sundarbans (West Bengal) were among the first nine Project Tiger reserves of 1973–74. Item 2 is wrong: Bhitarkanika (Odisha) is a mangrove national park and Ramsar site famous for saltwater crocodiles, not a tiger reserve. So (a), (c) and (d) fail.
Notice the current count: India has 58 tiger reserves (the latest being Madhav, MP, in March 2025). The 2022 estimate counted at least 3,167 tigers (about 3,682 by full analysis), about 75% of the world's wild tigers. Odisha's tiger reserves are Similipal and Satkosia. Trap: Bhitarkanika sounds like a big Odisha reserve but is for crocodiles.
Bhitarkanika is famous enough to look like a Tiger Reserve, but it is known for crocodiles and mangroves, not tigers.
Answer as per the official UPSC answer key.
Read the passage
Today’s developing economies use much less energy per capita than developed countries such as the United States did at similar incomes, showing the potential for lower-carbon growth. Adaptation and mitigation need to be integrated into a climate-smart development strategy that increases resilience, reduces the threat of further global warming, and improves development outcomes. Adaptation and mitigation measures can advance development, and prosperity can raise incomes and foster better institutions. A healthier population living in better-built houses and with access to bank loans and social security is better equipped to deal with a changing climate and its consequences. Advancing robust, resilient development policies that promote adaptation is needed today because changes in the climate, already begun, will increase even in the short term.
The spread of economic prosperity has always been intertwined with adaptation to changing ecological conditions. But as growth has altered the environment and as environmental change has accelerated, sustaining growth and adaptability demands greater capacity to understand our environment, generate new adaptive technologies and practices, and diffuse them widely. As economic historians have explained, much of humankind’s creative potential has been directed at adapting to the changing world. But adaptation cannot cope with all the impacts related to climate change, especially as larger changes unfold in the long term.
Countries cannot grow out of harm’s way fast enough to match the changing climate. And some growth strategies, whether driven by the government or the market, can also add to vulnerability — particularly if they overexploit natural resources. Under the Soviet development plan, irrigated cotton cultivation expanded in water-stressed Central Asia and led to the near disappearance of the Aral Sea, threatening the livelihoods of fishermen, herders and farmers. And clearing mangroves — the natural coastal buffers against storm surges — to make way for intensive farming or housing development, increases the physical vulnerability of coastal settlements, whether in Guinea or in Louisiana.
Which of the following conditions is/are necessary for the sustainable economic growth ?
- 1. Spreading of economic prosperity more.
- 2. Popularising/spreading of adaptive technologies widely.
- 3. Investing on research in adaptation and mitigation technologies.
Select the correct answer using the codes given below :
Answer (b) & explanation
Points 2 and 3 are correct (b). Step 1: the passage says sustaining growth 'demands greater capacity to understand our environment, generate new adaptive technologies and practices, and diffuse them widely'. Spreading adaptive technologies (2) and research to create them (3) both follow. Step 2: point 1, spreading prosperity more, is how the paragraph begins its story ('the spread of economic prosperity has always been intertwined with adaptation'). It is described as a fact of history, not named as a condition for sustainable growth. Step 3: so (a), (c) and (d) fail.
Tip: in 'necessary condition' questions, look for words like 'demands', 'requires' or 'needs' in the passage and match the options to what follows them.
Answer as per the official UPSC answer key.
Consider the following statements: The Third World War, if it ever starts will end very quickly with possible end of civilization. It is only the misuse of nuclear power which will trigger it. Based on the above statement, which one of the following inferences is correct?
Answer (a) & explanation
'Nuclear power will be used in the Third World War' is correct (a). Step 1: the statement says it is 'only the misuse of nuclear power' that will trigger the war. So if the war happens, nuclear power must have been misused, that is, used. Step 2: (b) is wrong: the statement says 'possible end of civilization', not certain end. (c) is wrong: it blames misuse, not the growth of nuclear power. Step 3: (d) is wrong: the statement says 'if it ever starts', leaving the war possible. So (b), (c) and (d) fail.
Tip: 'only X will trigger Y' means 'if Y, then X happened'. Also watch soft words like 'possible'; options that make them certain go too far.
Answer as per the official UPSC answer key.
You are handling a time-bound project. During the project review meeting, you find that the project is likely to get delayed due to lack of cooperation of the team members. You would...
Answer (a) & explanation
(a) and (b) are both correct (UPSC accepted both; no negative marking). Step 1: the project is time-bound and is slipping because the team is not cooperating. Step 2: (b) finding out why they are not cooperating lets you fix the root cause. (a) a clear warning makes it plain that non-cooperation must stop. Step 3: (c) asking for new team members wastes time and avoids leadership. (d) asking for an extension accepts the delay instead of solving it.
Tip: for these interpersonal items, pick the response that is lawful, honest and fixes the real problem through proper channels. Avoid options that give in, run away from duty or act without hearing the facts.
Answer as per the official UPSC answer key.
Which of the following special powers have been conferred on the Rajya Sabha by the Constitution of India?
Answer (b) & explanation
Option (b) is correct. As the House of the States, the Rajya Sabha alone can pass a resolution, by two-thirds of members present and voting, letting Parliament legislate on a State List subject in the national interest (Article 249). It alone can also authorise Parliament to create new All India Services (Article 312). (a) is wrong: changing a state's territory or name (Article 3) is done by ordinary law of both Houses. (c) is wrong: election procedure and pensions are set by laws of both Houses. (d) is wrong: the number of Election Commissioners is fixed by the President and law.
Notice the third power: when the Lok Sabha is dissolved, the Rajya Sabha alone can approve emergency proclamations. Trap: states' territory sounds federal, but both Houses decide it.
Answer as per the official UPSC answer key.
Which one of the following sets of elements was primarily responsible for the origin of life on the Earth?
Answer (b) & explanation
Carbon, hydrogen and nitrogen is correct (b). Life's building blocks, amino acids, sugars, fats and nucleic acids, are made mainly of carbon, hydrogen, nitrogen and oxygen, with phosphorus and sulphur. The Miller–Urey experiment (1953) made amino acids by passing sparks through methane, ammonia, hydrogen and water, mimicking the early Earth. (a) and (d) are wrong: sodium and potassium are minerals important for cells but not the core of organic molecules. (c) is wrong: calcium is not primary, and the early atmosphere had little free oxygen.
Notice the related theories: Oparin–Haldane's 'primordial soup', the RNA world, and life near deep-sea hydrothermal vents. Oxygen built up later through cyanobacteria in the Great Oxidation Event (about 2.4 billion years ago). Trap: oxygen is essential now but was not primary then.
Answer as per the official UPSC answer key.
Consider the following agricultural practices :
- 1. Contour bunding
- 2. Relay cropping
- 3. Zero tillage
In the context of global climate change, which of the above helps/help in carbon sequestration/storage in the soil?
Answer (b) & explanation
Zero tillage only is correct per UPSC's key (b), though the key is arguable. Zero tillage leaves the soil undisturbed and keeps crop residue on top, so soil organic carbon builds up instead of being oxidised to CO₂ (3). Contour bunding mainly checks soil erosion on slopes (1); by keeping topsoil and moisture in place it can help retain carbon indirectly, so some argue for (c). Relay cropping, sowing a second crop before the first is harvested, mainly uses the season fully (2). UPSC chose the practice whose direct aim is carbon storage.
Notice the related tools: Happy Seeder machines allow sowing into rice stubble in Punjab, cutting stubble burning. Cover crops, agroforestry and biochar also store soil carbon. The '4 per 1000' initiative (COP21) promotes soil carbon. Trap: erosion control is not the same as sequestration.
Answer as per the official UPSC answer key.
Consider the following statements: "Though quite expensive, television is not a luxury item, as one can learn many things through television". Which one of the following is a valid inference from the above statements?
Answer (d) & explanation
'Television is not a luxury item' is correct (d). Step 1: the statement plainly says television 'is not a luxury item' although it is expensive. That is a direct, valid inference. Step 2: (a) is wrong: 'though quite expensive' actually shows that expensive things are not always luxuries. (b) is wrong: one example (TV) does not prove a rule about all learning items. Step 3: (c) is wrong: the statement says one 'can learn many things' through TV, which does not make TV essential for learning. So (a), (b) and (c) fail.
Tip: the safest inference restates what is said. Options that turn one example into a rule ('all') or 'can help' into 'essential' go too far.
Answer as per the official UPSC answer key.
Read the passage
In a typical Western liberal context, deepening of democracy invariably leads to consolidation of ‘liberal values’. In the Indian context, democratization is translated into greater involvement of people not as ‘individuals’ which is a staple to liberal discourse, but as communities or groups. Individuals are getting involved in the public sphere not as ‘atomized’ individuals but as members of primordial communities drawn on religious or caste identity. Community-identity seems to be the governing force. It is not therefore surprising that the so-called peripheral groups continue to maintain their identities with reference to the social groups (caste, religion or sect) to which they belong while getting involved in the political processes despite the fact that their political goals remain more or less identical. By helping to articulate the political voice of the marginalized, democracy in India has led to ‘a loosening of social strictures’ and empowered the peripherals to be confident of their ability to improve the socio-economic conditions in which they are placed. This is a significant political process that had led to a silent revolution through a meaningful transfer of power from the upper caste elites to various subaltern groups within the democratic framework of public governance.
Greater democratization in India has not necessarily led to
Answer (b) & explanation
(b) is correct. Step 1: the passage says 'community-identity seems to be the governing force' and groups keep their caste or religious identity even as they join politics. So democratization has not made community identity irrelevant. Step 2: (a) is close, since caste identities have also not been diluted, but (b) uses the passage's own words ('governing force') and is the key. Step 3: (c) is wrong: the passage says power has moved from upper-caste elites to subaltern groups, so elites have in fact been weakened. (d) is wrong: the passage does not compare hereditary and class identities. So (a), (c) and (d) fail.
Tip: when two options look similar, choose the one closest to the passage's wording.
Answer as per the official UPSC answer key.
With reference to consumers’ rights/privileges under the provisions of law in India, which of the following statements is/are correct?
- 1. Consumers are empowered to take samples for food testing.
- 2. When a consumer files a complaint in any consumer forum, no fee is required to be paid.
- 3. In case of death of a consumer, his/her legal heir can file a complaint in the consumer forum on his/her behalf.
Select the correct answer using the codes given below :
Answer (c) & explanation
Statements 1 and 3 are correct (c). Under food-safety law, a consumer can buy a sample and get it tested at an accredited laboratory, paying a fee (1). Under consumer law, the legal heir or representative of a deceased consumer may file a complaint (3). Statement 2 is wrong: consumer commissions charge a fee that rises with the value of the claim. So (a), (b) and (d) fail.
Notice the current law: the Consumer Protection Act, 2019 replaced the 1986 Act, renamed forums as District, State and National Commissions, set up the Central Consumer Protection Authority, and allows e-filing (e-Daakhil). Since 2020 the rules waive the fee for claims up to ₹5 lakh, so statement 2 is still wrong as a general rule. Trap: 'no fee' is too absolute.
Answer as per the official UPSC answer key.
Government of India encourages the cultivation of ‘sea buckthorn’. What is the importance of this plant?
- 1. It helps in controlling soil erosion and in preventing desertification.
- 2. It is a rich source of biodiesel.
- 3. It has nutritional value and is well-adapted to live in cold areas of high altitudes.
- 4. Its timber is of great commercial value.
Which of the statements given above is/are correct?
Answer (c) & explanation
Statements 1 and 3 are correct (c). Sea buckthorn is a thorny shrub of cold deserts such as Ladakh, Lahaul-Spiti and Sikkim. Its deep, spreading roots bind soil and help check erosion and desertification (1). Its orange berries are rich in vitamin C, omega oils and antioxidants, used in juices, medicines and cosmetics, and it thrives in cold, high-altitude areas (3). Statement 2 is wrong: it is not a biodiesel crop. Statement 4 is wrong: as a shrub, it has no commercial timber value. So (a), (b) and (d) fail.
Notice the local names: 'Leh berry' in Ladakh. The DRDO's DIHAR at Leh promotes it, and it fixes nitrogen in poor soils. Trap: its oil is medicinal, not fuel.
Answer as per the official UPSC answer key.
Which of the following measures would result in an increase in the money supply in the economy?
- 1. Purchase of government securities from the public by the Central Bank
- 2. Deposit of currency in commercial banks by the public
- 3. Borrowing by the government from the Central Bank
- 4. Sale of government securities to the public by the Central Bank
Select the correct answer using the codes given below :
Answer (c) & explanation
Items 1 and 3 are correct (c). When the central bank buys government securities from the public, it pays with new money, so supply rises (1). When the government borrows from the central bank, the RBI creates new money (monetisation of deficit), so supply rises (3). Item 4 is the reverse: selling securities absorbs money. Item 2 is neutral: depositing cash in a bank only changes money's form from currency to deposits; UPSC treats it as no increase, though it could later enable more lending. So (a), (b) and (d) fail.
Notice the tools: these are open market operations. The 1997 agreement ended automatic monetisation through ad hoc Treasury Bills, and the FRBM Act bars RBI from primary market purchases except in special cases. Trap: deposits feel like 'more money', but the total is unchanged.
Answer as per the official UPSC answer key.
Read the passage
Education, without a doubt, has an important functional, instrumental and utilitarian dimension. This is revealed when one asks questions such as ‘what is the purpose of education ?’. The answers, too often, are ‘to acquire qualifications for employment/upward mobility’, ‘wider/higher (in terms of income) opportunities’, and ‘to meet the needs for trained human power in diverse fields for national development’. But in its deepest sense education is not instrumentalist. That is to say, it is not to be justified outside of itself because it leads to the acquisition of formal skills or of certain desired psychological – social attributes. It must be respected in itself. Education is thus not a commodity to be acquired or possessed and then used, but a process of inestimable importance to individuals and society, although it can and does have enormous use-value. Education then, is a process of expansion and conversion, not in the sense of converting or turning students into doctors or engineers, but the widening and turning out of the mind — the creation, sustenance and development of self-critical awareness and independence of thought. It is an inner process of moral – intellectual development.
According to the passage, education must be respected in itself because
Answer (c) & explanation
'An inner process of moral and intellectual development' is correct (c). Step 1: the passage says education 'must be respected in itself' and ends: 'It is an inner process of moral – intellectual development.' That is the reason it deserves respect for its own sake. Step 2: (a) jobs and (b) mobility and status are exactly the outside justifications the author says education does not need. Step 3: since (a) and (b) are wrong, (d) 'all of the above' also fails.
Tip: 'respected in itself' means valued for its own nature, not for what it brings. Any option about rewards like jobs, income or status is the opposite of that idea.
Answer as per the official UPSC answer key.
Read the passage
Most champions of democracy have been rather reticent in suggesting that democracy would itself promote development and enhancement of social welfare — they have tended to see them as good but distinctly separate and largely independent goals. The detractors of democracy, on the other hand, seemed to have been quite willing to express their diagnosis of what they see as serious tensions between democracy and development. The theorists of the practical split — “Make up your mind : do you want democracy, or instead, do you want development ?” — often came, at least to start with, from East Asian countries, and their voice grew in influence as several of these countries were immensely successful — through the 1970s and 1980s and even later — in promoting economic growth without pursuing democracy.
To deal with these issues we have to pay particular attention to both the content of what can be called development and to the interpretation of democracy (in particular to the respective roles of voting and of public reasoning). The assessment of development cannot be divorced from the lives that people can lead and the real freedom that they enjoy. Development can scarcely be seen merely in terms of enhancement of inanimate objects of convenience, such as a rise in the GNP (or in personal incomes), or industrialization — important as they may be as means to the real ends. Their value must depend on what they do to the lives and freedom of the people involved, which must be central to the idea of development.
If development is understood in a broader way, with a focus on human lives, then it becomes immediately clear that the relation between development and democracy has to be seen partly in terms of their constitutive connection, rather than only through their external links. Even though the question has often been asked whether political freedom is “conducive to development”, we must not miss the crucial recognition that political liberties and democratic rights are among the “constituent components” of development. Their relevance for development does not have to be established indirectly through their contribution to the growth of GNP.
According to the passage, what should be the ultimate assessment/aim/view of development ?
Answer (d) & explanation
'Extent of real freedom' is correct (d). Step 1: the passage says development 'cannot be divorced from the lives that people can lead and the real freedom that they enjoy', which 'must be central to the idea of development'. Step 2: (a) incomes and industrial growth and (b) GNP are called only 'means to the real ends', not the aim itself. The HDI is not mentioned. Step 3: (c) savings and consumption are not mentioned at all. So (a), (b) and (c) fail.
Tip: the author is drawing on the idea of 'development as freedom'. When a passage separates means from ends, the 'ultimate aim' question always wants the end, not the means like GNP or income.
Answer as per the official UPSC answer key.
Read the passage
For fourteen and a half months I lived in my little cell or room in the Dehradun jail, and I began to feel as if I was almost a part of it. I was familiar with every bit of it, I knew every mark and dent on the whitewashed walls and on the uneven floor and the ceiling with its moth-eaten rafters. In the little yard outside I greeted little tufts of grass and odd bits of stone as old friends. I was not alone in my cell, for several colonies of wasp and hornets lived there, and many lizards found a home behind the rafters, emerging in the evenings in search of prey.
Which of the following explains best the sentence in the passage “I was almost a part of it” ?
Answer (b) & explanation
(b) is correct. Step 1: the very next sentence explains the phrase: 'I was familiar with every bit of it, I knew every mark and dent on the… walls'. Feeling part of the cell means knowing it in every detail. Step 2: (a) 'not alone' refers to the wasps and lizards, a different point. (c) greeting grass as friends is about the yard outside, not the cell. Step 3: (d) 'felt quite at home' is a close distractor, but the passage never says he felt comfortable; it stresses familiarity. So (a), (c) and (d) fail.
Tip: when asked to explain a phrase, look at the sentence right after it. Authors often explain their own words there.
Answer as per the official UPSC answer key.
Which of the following is/are cited by the scientists as evidence/evidences for the continued expansion of universe?
- 1. Detection of microwaves in space
- 2. Observation of redshift phenomenon in space
- 3. Movement of asteroids in space
- 4. Occurrence of supernova explosions in space
Select the correct answer using the codes given below :
Answer (a) & explanation
Microwaves and redshift are correct (a). Light from distant galaxies is red-shifted: its wavelength is stretched because the galaxies are moving away, faster the farther they are (Hubble's law) (2). The cosmic microwave background radiation, found in 1965, is the cooled afterglow of the Big Bang, spread evenly across the sky (1). Statement 3 is wrong: asteroids move within our solar system and say nothing about expansion. Statement 4 is wrong: supernovae alone are not evidence, though Type Ia supernovae used as distance markers showed in 1998 that expansion is accelerating. So (b), (c) and (d) fail.
Notice the puzzle: this acceleration is blamed on dark energy, and the 'Hubble tension' is a mismatch in measured expansion rates. Trap: (4) hides a partial truth.
Answer as per the official UPSC answer key.
The endeavour of ‘Janani Suraksha Yojana’ Programme is
- 1. to promote institutional deliveries
- 2. to provide monetary assistance to the mother to meet the cost of delivery
- 3. to provide for wage loss due to pregnancy and confinement
Which of the statements given above is/are correct?
Answer (a) & explanation
Statements 1 and 2 are correct (a). Janani Suraksha Yojana (2005, under the National Rural Health Mission) promotes institutional deliveries to cut maternal and infant deaths (1), and gives cash assistance to poor pregnant women for delivery in a health facility (2). The ASHA who escorts her also gets an incentive. Statement 3 is wrong: compensation for wage loss during pregnancy came under a different scheme, the Indira Gandhi Matritva Sahyog Yojana (2010), now the Pradhan Mantri Matru Vandana Yojana (2017), which pays ₹5,000 for the first child and ₹6,000 for a second girl child under Mission Shakti. So (b), (c) and (d) fail.
Notice the outcome: institutional births rose to about 89% (NFHS-5), and India's MMR fell to about 93 per lakh (2019–21). Trap: two maternity schemes are blended into one.
Answer as per the official UPSC answer key.