Science and Technology: UPSC Previous Year Questions (Prelims)
473 previous year UPSC Prelims Science and Technology questions are on this page, from 1996 to 2025, in 21 chapters. Biology: Zoology is the largest, followed by Miscellaneous (energy, vehicles and materials), Botany, Space and ICT. Recent papers lean on applied technology in the news, while older ones lean on school-level physics, chemistry and biology. Filter by chapter to revise one area at a time.
Explanations state facts as of the year each question was asked; words like “recently” refer to that year.
Showing 91–100 of 473 questions
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UPSC 2017Science and Technology · Biotechnology
Q91. With reference to agriculture in India, how can the technique of ‘genome sequencing’, often seen in the news, be used in the immediate future? 1. Genome sequencing can be used to identify genetic markers for disease resistance and drought tolerance in various crop plants. 2. This technique helps in reducing the time required to develop new varieties of crop plants. 3. It can be used to decipher the host pathogen relationships in crops. Select the correct answer using the code given below:
Explanation
Genome sequencing is the process of determining the complete DNA sequence of an organism’s genome by identifying the precise order of nucleotides--adenine (A), thymine (T), cytosine (C), and guanine (G)--that make up its genetic material. This comprehensive analysis provides critical insights into an organism’s genetic information, including variations, mutations, and functional elements such as genes and regulatory regions.
Statement 1 is correct: Genome sequencing can be used to identify specific genes or genetic markers in crops that confer resistance to diseases or tolerance to environmental stresses like drought. This allows plant breeders to select plants with these beneficial traits and accelerate crop improvement.
Statement 2 is correct: Genome sequencing speeds up the breeding process. Instead of relying on traditional trial-and-error methods to cross plants, scientists can use genome information to make more precise genetic selections.
Statement 3 is correct: Genome sequencing can also help researchers understand how crops interact with pathogens (like bacteria, fungi, and viruses). By mapping the genomes of both the host plant and the pathogen, researchers can identify the genes involved in defense mechanisms and the pathogen’s strategies for evading these defenses.
Exam tip:
In science and technology UPSC questions, the NOT approach is most applicable. You can try, The "NOT" approach for all statements, this tests the improbability of negating a statement--if denying its impact seems highly unlikely, the statement is plausibly true. And Until un-less something absolutely weird is mentioned, assume all are right. In addition, "Can’’ and "Some" = possibility logic, not absolute. If even one species of organism does something, the statement is likely correct. UPSC uses " can" and "some" to lower the burden of proof harder to eliminate. Hence all statements are likely correct.
UPSC 2017Science and Technology · Health
Q92. Consider the following statements: 1. In tropical regions, Zika virus disease is transmitted by the same mosquito that transmits dengue. 2. Sexual transmission of Zika virus disease is possible. Which of the statements given above is/are correct?
Explanation
Statement 1 is correct: The Zika virus is primarily transmitted by the Aedes aegypti mosquito which is also the primary vector for dengue fever. This mosquito species thrives in tropical and subtropical regions, making it a common carrier for both diseases. The Aedes aegypti mosquito is well-adapted to urban environments and breeds in stagnant water, such as in containers, flower pots, and discarded tires.
Statement 2 is correct: Zika virus can be transmitted through sexual contact unlike other mosquito-borne diseases like dengue or chikungunya. The virus can remain in semen for an extended period even after symptoms have resolved. Zika virus infection during pregnancy can cause severe birth defects such as microcephaly.
UPSC 2017Science and Technology · Diseases
Q93. Consider the following pairs:
Commonly used/ consumed materials
Unwanted or controversial chemicals likely to be found in them
1. Lipstick
Lead
2. Soft drinks
Brominated vegetable oils
3. Chinese fast food
Monosodium glutamate
Which of the pairs given above is/are correctly matched?
Explanation
Pair 1 is correctly matched: Lip items like lipsticks and other cosmetics including eye shadow, blush, compact powder, shampoo, and body lotion frequently include the contaminant lead.
Pair 2 is correctly matched: In some sodas and soft drinks, the citrus flavour is sometimes prevented from breaking out by the food additive brominated vegetable oil.
Pair 3 is correctly matched: MSG is commonly added to Chinese fast food and other processed foods to enhance flavor. While it is generally recognized as safe, some individuals may experience sensitivity to MSG, leading to symptoms like headaches or nausea.
UPSC 2017Science and Technology · Information and Communication Technology
Q94. Which of the following statements is/are correct regarding Smart India Hackathon 2017? 1. It is a centrally sponsored scheme for developing every city of our country into Smart Cities in a decade. 2. It is an initiative to identify new digital technology innovations for solving the many problems faced by our country. 3. It is a programme aimed at making all the financial transactions in our country completely digital in a decade. Select the correct answer using the code given below:
Explanation
Statement 1 is incorrect:
Smart India Hackathon (SIH) 2017 was not a centrally sponsored scheme for developing Smart Cities. It is a nationwide initiative to promote innovation and problem-solving among students by leveraging digital technology. The event was organized by the Ministry of Human Resource Development (MHRD) and the All India Council for Technical Education (AICTE) in collaboration with other government bodies.
Statement 2 is correct: SIH was launched to encourage young minds to develop innovative solutions to challenges faced by ministries, departments, and public sector organizations. It provided a platform for students to collaborate on real-world problems using digital technology.
Statement 3 is incorrect: The Smart India Hackathon is not related to making financial transactions digital. The initiative aimed at promoting digital financial transactions is the Digital India campaign, which includes programs like Unified Payments Interface (UPI), BHIM app, and Aadhaar-enabled payment systems.
UPSC 2017Science and Technology · Information and Communication Technology
Q95. In India, it is legally mandatory for which of the following to report on cyber security incidents? 1. Service providers2. Data centres3. Body corporate Select the correct answer using the code given below:
Explanation
It is legally mandatory for service providers, data centres, and body corporate to report cybersecurity incidents to the Indian Computer Emergency Response Team (CERT-In). Under the Information Technology (IT) Act, 2000, and the Information Technology (The Indian Computer Emergency Response Team and Manner of Performing Functions and Duties) Rules, 2013. CERT-In is the national nodal agency for responding to cybersecurity incidents and ensuring the security of India’s cyber infrastructure.
Additional insight:
The Indian Computer Emergency Response Team (CERT) imposes rules on service providers, intermediaries, data centres, body corporate or persons who provide the information called for or comply with the direction of CERT. They need to report cyber incidents within a reasonable time so that CERT-In may have scope for timely action.
UPSC 2017Science and Technology · Space and Space Technology
Q96. The terms ‘Event Horizon’, ‘Singularity’, ‘String Theory’ and ‘Standard Model’ are sometimes seen in the news in the context of
Explanation
The terms ‘Event Horizon’, ‘Singularity’, ‘String Theory’, and ‘Standard Model’ are primarily associated with the observation and understanding of the Universe. Event Horizon is the boundary of a black hole where escape velocity exceeds the speed of light and thus nothing, including light, can escape once crossed. A gravitational singularity is a region in space where matter is infinitely dense, and gravitational forces become infinite. It is found at the center of black holes, where spacetime curvature becomes infinite, and the equations of general relativity fail to provide a meaningful description. String Theory is a theoretical framework in physics that attempts to reconcile quantum mechanics and general relativity by positing that fundamental particles are not point-like but rather one-dimensional "strings." It is a candidate for a theory of everything, aiming to explain all fundamental forces and particles in the Universe. Standard Model is the theory in particle physics that describes three of the four known fundamental forces (electromagnetic, weak, and strong interactions) and classifies all known elementary particles. It is a cornerstone of modern physics and helps explain the behavior of matter and energy in the Universe.
UPSC 2017Science and Technology · Space and Space Technology
Q97. What is the purpose of the ‘evolved Laser Interferometer Space Antenna (eLISA)’ project?
Explanation
The evolved Laser Interferometer Space Antenna (eLISA) is a mission led by the European Space Agency (ESA) to detect and measure gravitational waves. Gravitational waves are ripples in spacetime caused by massive cosmic events, such as merging black holes or neutron stars. eLISA aims to provide a new way of observing the universe by directly measuring these waves which are otherwise invisible to traditional telescopes. Unlike ground-based detectors like LIGO, eLISA will operate in space, allowing it to observe lower-frequency gravitational waves that cannot be detected on Earth.
Additional insight:
Other Projects to Measure The Gravitational Waves Project Country (Locations) Remarks LIGO (Laser Interferometer Gravitational-Wave Observatory) Observatories in the USA and Italy Made the first direct detection of gravitational waves in 2015. LIGO-India India, Planned Ground-based interferometer that collaborates with LIGO to detect gravitational waves. Virgo Italy Virgo collaborates with LIGO and KAGRA to pinpoint the origins of these waves. KAGRA (Kamioka Gravitational Wave Detector) Japan Designed to detect gravitational waves and contribute to the global network of detectors Pulsar Timing Arrays (PTAs) Australia, China, India, South Africa, and the United States. These are networks of millisecond pulsars used to detect low-frequency gravitational waves.
UPSC 2017Science and Technology · Miscellaneous
Q98. Organic Light Emitting Diodes (OLEDs) are used to create digital displays in many devices. What are the advantages of OLED displays over Liquid Crystal displays? 1. OLED displays can be fabricated on flexible plastic substrates. 2. Roll-up displays embedded in clothing can be made using OLEDs. 3. Transparent displays are possible using OLEDs. Select the correct answer using the code given below:
Explanation
Statement 1 is correct: OLEDs can be manufactured on flexible materials such as polyethylene terephthalate (PET), which allows the creation of foldable and bendable screens. Unlike LCDs, which require rigid glass substrates, OLEDs can use lightweight and flexible plastics, enabling the development of innovative designs like foldable smartphones and rollable displays.
Statement 2 is correct: The flexibility and thinness of OLEDs make them suitable for rollable screens that can be integrated into textiles or wearable devices. This innovation enables the creation of electronic clothing or fabrics with embedded displays, providing new possibilities in wearable technology.
Statement 3 is correct: OLED technology supports the development of transparent displays because it does not rely on a backlight. OLEDs produce light on their own, making it possible to create see-through screens that overlay digital content on real-world environments.
UPSC 2016Science and Technology · Biotechnology
Q99. Which of the following statements is/are correct? Viruses can infect 1. Bacteria 2. Fungi 3. Plants Select the correct answer using the code given below.
Explanation
Viruses are obligate intracellular parasites, meaning they require a host cell to replicate. They can infect bacteria, fungi, plants, animals, and other viruses. Viruses that infect bacteria are called bacteriophages (or simply phages). These viruses play a crucial role in regulating bacterial populations. Phages attach to bacterial cells, inject their genetic material, and hijack the bacterial machinery to replicate themselves. This process often leads to the destruction (lysis) of the bacterial cell. Viruses that infect fungi are called mycoviruses (Mycophages). They do not have an extracellular phase (i.e., they lack the ability to move outside fungal cells). They are linked to plant diseases because they weaken fungi that help plant growth. Cryphonectria hypovirus 1 (CHV1) infects chestnut blight fungus (Cryphonectria parasitica). Plant viruses are well-known pathogens that cause significant economic losses in agriculture such as the Tobacco Mosaic Virus (TMV), Potato Virus Y (PVY), and Tomato Spotted Wilt Virus (TSWV). Plant viruses are typically transmitted by insects, nematodes, or through contaminated seeds and tools. They infect plant cells disrupting their normal cellular functions and cause symptoms such as leaf curling, stunting, and mosaic patterns.
UPSC 2016Science and Technology · Biotechnology
Q100. In the context of the developments in Bioinformatics, the term ‘transcriptome’, sometimes seen in the news, refers to:
Explanation
Option (b) is correct: A transcriptome is the full range of messenger RNA(mRNA) molecules expressed by an organism. The term "transcriptome" can also be used to describe the array of mRNA transcripts produced in a particular cell or tissue type. Transcriptome analysis (RNA sequencing or RNA-Seq) is a key tool in bioinformatics for studying gene expression, identifying biomarkers, and understanding cellular functions.
Option (a), (c) and (d) are incorrect:
Genome editing involves enzymes like CRISPR-Cas9, TALENs, etc which are used to modify DNA sequences. These enzymes are tools for targeted genetic modifications. Transcriptome doesn’t relate to enzymes used in editing Gene expression involves the processes of transcription (DNA to mRNA) and translation (mRNA to proteins). It includes regulatory mechanisms like transcription factors, epigenetic modifications, and post-transcriptional processing. Mutations are changes in the DNA sequence caused by errors during replication, environmental factors, or chemical agents.
Answer key for these questions
Q
UPSC year
Correct answer
91
2017
(d) 1, 2 and 3
92
2017
(c) Both 1 and 2
93
2017
(d) 1, 2 and 3
94
2017
(b) 2 only
95
2017
(d) 1, 2 and 3
96
2017
(a) Observation and understanding of the Universe
97
2017
(b) To detect gravitational waves
98
2017
(c) 1, 2 and 3
99
2016
(d) 1, 2 and 3
100
2016
(b) The full range of mRNA molecules expressed by an organism
What UPSC has tested in Science and Technology
Recent questions are application-based: electric vehicles, quantum computing, monoclonal antibodies, CRISPR, gravitational waves and space missions.
Older questions test school science: buoyancy, scattering of light, atomic structure and common compounds.
In Physics and Chemistry, explanations that depend on formulas or equations are left out where the original text could not be shown reliably.
The 2025 paper’s Science and Technology questions covered EVs, UAVs, coal gasification, CL-20, Majorana 1, monoclonal antibodies, GAGAN and ISRO missions.
Frequently asked questions
How many previous year UPSC questions are there on Science and Technology?
This page covers 473 previous year UPSC Prelims GS Paper-I questions on Science and Technology, asked from 1996 to 2025. Each has the correct answer and an explanation.
Which Science and Technology chapters have the most questions?
Biology: Zoology has the most with 115 questions, then Miscellaneous with 68, Biology: Botany with 37, Space and Space Technology with 36 and Information and Communication Technology with 32.
How should I revise Science and Technology from these questions?
Take the technology chapters first, because recent papers favour them, then use the Physics, Chemistry and Biology chapters for basics. Each chapter page lists the facts UPSC has tested and has an answer key.
Why do some Chemistry and Physics questions look missing?
Questions whose explanations depend on chemical formulas or equations that could not be shown correctly were left out, rather than risk a wrong formula. The questions that remain have clear explanations in plain words.
