UPSC Prelims 2019 Science and Technology questions: topic-wise weightage
UPSC Prelims 2019 asked 13 science and technology questions in GS Paper I, spread over 2 topics. See the science and technology weightage for 2019 below, then attempt each question with the official answer and an explanation.
Science and Technology 2019: questions by topic
Counted from the 13 questions on this page, tagged by topic in the Battle IAS PYQ bank.
Seeing 13 Science and Technology questions spread over 2 topics can feel overwhelming. That's exactly why the Battle IAS PYQ Book maps every question topic by topic, so you know what to study first. Download free sample
Biology, health and biotechnology 7
Consider the following statements :
- 1. According to the Indian Patents Act, a biological process to create a seed can be patented in India.
- 2. In India, there is no Intellectual Property Appellate Board.
- 3. Plant varieties are not eligible to be patented in India.
Which of the statements given above is/are correct?
Answer (c) & explanation
Only statement 3 is correct (c). Statement 1 is wrong because Section 3(j) of the Patents Act, 1970 excludes plants, animals, seeds, varieties, and essentially biological processes for producing them. Statement 2 was wrong in 2019, because the Intellectual Property Appellate Board (IPAB) existed, set up in 2003. It was abolished only in 2021 by the Tribunals Reforms Act, and its work went to the High Courts. Statement 3 is right because plant varieties cannot be patented. They are protected under the Protection of Plant Varieties and Farmers' Rights (PPV&FR) Act, 2001, a sui generis law allowed by TRIPS.
Notice the PepsiCo case: in 2024, the Delhi High Court upheld the cancellation of its registration for the FL-2027 potato variety, used for Lay's chips.
When an institution has since been abolished, answer from the year the question was set.
Answer as per the official UPSC answer key.
The word ‘Denisovan’ is sometimes mentioned in media in reference to
Answer (b) & explanation
Denisovans are an early human species (b). They are an archaic human species, closely related to the Neanderthals. They were first identified in 2010 from DNA in a finger bone found in Denisova Cave, in Siberia's Altai Mountains. They interbred with modern humans. Traces of their DNA survive in people of Melanesia, Papua New Guinea and parts of Asia. A Denisovan gene, EPAS1, helps Tibetans live at high altitude. They are not dinosaurs (a), a North-East Indian cave (c), or a geological period (d).
Notice the newer finds: a Denisovan jaw from Tibet's Baishiya Cave, and the Harbin skull from China, confirmed as Denisovan in 2025. Svante Pääbo won the 2022 Medicine Nobel for this work.
Answer as per the official UPSC answer key.
With reference to the recent developments in science, which one of the following statements is not correct?
Answer (a) & explanation
Option (a) is the statement that is not correct. Option (b) is correct because scientists can synthesise DNA in the lab, and Craig Venter's team made a bacterium with a fully synthetic genome (2010). Option (c) is correct because the polymerase chain reaction (PCR) copies DNA outside a living cell. Option (d) is correct because plant and animal cells can be grown and made to divide in tissue culture in petri dishes. Recombinant DNA does join genes from different species, but UPSC's key treats building a working chromosome by splicing segments from different species as not possible.
Notice the related news: genome-edited rice varieties released by India in 2025, and synthetic biology research on yeast with synthetic chromosomes (Sc2.0).
Answer as per the official UPSC answer key.
‘RNA interference (RNAi)’ technology has gained popularity in the last few years. Why?
- 1. It is used in developing gene silencing therapies.
- 2. It can be used in developing therapies for the treatment of cancer.
- 3. It can be used to develop hormone replacement therapies.
- 4. It can be used to produce crop plants that are resistant to viral pathogens.
Select the correct answer using the code given below.
Answer (a) & explanation
Statements 1, 2 and 4 are correct (a). RNA interference (RNAi) uses small RNA molecules to silence specific genes by destroying their messenger RNA. It is the basis of gene-silencing drugs such as patisiran (1), approved in 2018. It is being tested in cancer therapies to switch off genes that help tumours grow (2). It is used to make virus-resistant crops, such as papaya resistant to ringspot virus (4). Statement 3 is wrong because hormone replacement adds a missing hormone, rather than switching a gene off, so RNAi plays no role.
Fire and Mello won the 2006 Medicine Nobel for discovering RNAi. Notice the related microRNA discovery, which won Ambros and Ruvkun the 2024 Medicine Nobel.
Answer as per the official UPSC answer key.
Which of the following are the reasons for the occurrence of multi-drug resistance in microbial pathogens in India?
- 1. Genetic predisposition of some people
- 2. Taking incorrect doses of antibiotics to cure diseases
- 3. Using antibiotics in livestock farming
- 4. Multiple chronic diseases in some people
Select the correct answer using the code given below.
Answer (b) & explanation
Statements 2 and 3 are correct (b). Antimicrobial resistance develops in the microbes themselves, when antibiotics kill weak germs and leave the resistant ones to multiply. In India, causes include wrong or incomplete doses of antibiotics (2), easy over-the-counter sales, and heavy antibiotic use in poultry and livestock to boost growth (3). Statements 1 and 4 are wrong because a person's genes or chronic diseases can make infections worse, but they do not make microbes resistant.
Notice India's response: the National Action Plan on AMR (2017, version 2.0 in 2025), the Chennai Declaration, the Red Line campaign on medicine packs, and the ban on colistin as a growth promoter in animals (2019). Kerala was the first state with its own AMR plan.
Answer as per the official UPSC answer key.
What is Cas9 protein that is often mentioned in news?
Answer (a) & explanation
Cas9 is a molecular scissors for gene editing (a). Cas9 is an enzyme found in bacteria, which use it to defend against viruses. A guide RNA leads Cas9 to a matching DNA sequence, where it cuts both strands. Scientists can then remove, fix or add genes. This is the CRISPR-Cas9 system, which won Charpentier and Doudna the 2020 Chemistry Nobel. It is not a biosensor (b), though related Cas proteins are used in tests. It is not a pest-resistance gene (c) like Bt, nor a herbicide (d).
Notice India's uses: the FELUDA COVID test used a related Cas protein, and India released two genome-edited rice varieties in 2025. The USA approved Casgevy, the first CRISPR therapy for sickle cell disease, in 2023.
Answer as per the official UPSC answer key.
Which one of the following statements is not correct?
Answer (b) & explanation
Option (b) is not correct, so it is the answer. Hepatitis B has had a safe, effective vaccine since the 1980s, and India gives it at birth under the Universal Immunisation Programme. Hepatitis C has no vaccine, but it can now be cured with antiviral drugs. Option (a) is correct because Hepatitis B spreads through blood, sex and from mother to child, much like HIV. Option (c) is correct because about 300 million people live with hepatitis B or C, far more than the roughly 40 million with HIV. Option (d) is correct because both can stay silent for years before causing cirrhosis or liver cancer.
Notice India's National Viral Hepatitis Control Programme (2018) and the WHO goal of eliminating hepatitis by 2030.
Answer as per the official UPSC answer key.
Space technology 6
For the measurement/estimation of which of the following are satellite images/remote sensing data used?
- 1. Chlorophyll content in the vegetation of a specific location
- 2. Greenhouse gas emissions from rice paddies of a specific location
- 3. Land surface temperatures of a specific location
Select the correct answer using the code given below.
Answer (d) & explanation
Satellites measure all three (d). Chlorophyll in vegetation (1) is estimated from how plants reflect red and near-infrared light, using indices such as NDVI. Healthy leaves reflect more near-infrared. Greenhouse gases such as methane from flooded rice paddies (2) are detected by sensors that measure how these gases absorb sunlight, on satellites such as Sentinel-5P, GOSAT and GHGSat. Land surface temperature (3) is measured using thermal infrared bands, as on Landsat and INSAT-3D. So no option leaving one out is correct.
Notice India's growing role: ISRO's Bhuvan platform, crop yield estimates under FASAL, and the NISAR radar satellite launched with NASA in July 2025.
Answer as per the official UPSC answer key.
With reference to communication technologies, what is/are the difference/differences between LTE (Long-Term Evolution) and VoLTE (Voice over Long-Term Evolution)?
- 1. LTE is commonly marketed as 3G and VoLTE is commonly marketed as advanced 3G.
- 2. LTE is data-only technology and VoLTE is voice-only technology.
Select the correct answer using the code given below.
Answer (d) & explanation
Neither statement is correct (d). Statement 1 is wrong because LTE, short for Long-Term Evolution, is marketed as 4G, not 3G. VoLTE is a service on that 4G network, not "advanced 3G". Statement 2 is wrong because LTE is mainly for data, but VoLTE carries voice calls as data packets over the same 4G network. So voice and data run together, giving clearer HD voice, faster call set-up, and data use during calls. VoLTE is not voice-only.
India's 4G growth took off when Reliance Jio launched an all-VoLTE network in 2016. Notice the newer steps: 5G rolled out from October 2022, BSNL's indigenous 4G stack went live in 2025, and VoNR carries voice over 5G.
Answer as per the official UPSC answer key.
In the context of digital technologies for entertainment, consider the following statements :
- 1. In Augmented Reality (AR), a simulated environment is created and the physical world is completely shut out.
- 2. In Virtual Reality (VR), images generated from a computer are projected onto real-life objects or surroundings.
- 3. AR allows individuals to be present in the world and improves the experience using the camera of smart-phone or PC.
- 4. VR closes the world, and transposes an individual, providing complete immersion experience.
Which of the statements given above is/are correct?
Answer (b) & explanation
Statements 3 and 4 are correct (b). Statements 1 and 2 swap the definitions. Augmented Reality (AR) keeps you in the real world and adds digital images on top of it, usually through a phone camera or smart glasses (3). Examples are Pokémon Go, Snapchat filters, and apps that show furniture in your room. Virtual Reality (VR) shuts out the real world and places you in a fully simulated one, usually through a headset, giving complete immersion (4).
Mixed reality combines both, letting digital objects interact with the real world, as in Apple Vision Pro. Notice the uses beyond games: training surgeons and pilots, virtual tours of heritage sites, and India's AVGC-XR policy for animation, gaming and extended reality.
Answer as per the official UPSC answer key.
Consider the following statements :
A digital signature is
- 1. an electronic record that identifies the certifying authority issuing it
- 2. used to serve as a proof of identity of an individual to access information or server on Internet
- 3. an electronic method of signing an electronic document and ensuring that the original content is unchanged
Which of the statements given above is/are correct?
Answer (c) & explanation
Only statement 3 is correct (c). A digital signature is an electronic method of signing a document using public-key cryptography. The signer uses a private key, and anyone can check it with the matching public key. It proves who signed and shows the content has not been changed (3). Statement 1 is wrong because the record that identifies the certifying authority is the digital signature certificate, not the signature itself. Statement 2 is wrong because identity for logging in to a server is proved by certificates, passwords and logins, not a digital signature as such.
In India, digital signatures are legally valid under the IT Act, 2000. The Controller of Certifying Authorities licenses issuers. Notice Aadhaar-based eSign and DigiLocker, used widely for e-governance.
Do not confuse the signature with the certificate. Statements 1 and 2 describe what a certificate does.
Answer as per the official UPSC answer key.
In the context of wearable technology, which of the following tasks is/are accomplished by wearable devices?
- 1. Location identification of a person
- 2. Sleep monitoring of a person
- 3. Assisting the hearing impaired person
Select the correct answer using the code given below.
Answer (d) & explanation
Wearables do all three tasks (d). Smartwatches and fitness bands use GPS to identify a person's location (1), useful for tracking runs or finding children and elderly people. They monitor sleep using motion sensors and heart-rate sensors (2). Smart hearing aids and earbuds with hearing-assist modes help people with hearing loss (3); for example, some AirPods models were approved as hearing aids in 2024. So any option leaving one out is wrong.
Wearables also measure heart rate, blood oxygen and ECG, and detect falls. Notice the issues: privacy of health data under the DPDP Act, and India's growing home-grown wearable makers such as boAt and Noise, helped by the PLI scheme for electronics.
Answer as per the official UPSC answer key.
Recently, scientists observed the merger of giant ‘blackholes’ billions of light-years away from the Earth. What is the significance of this observation?
Answer (b) & explanation
The merger proved gravitational waves exist (b). In September 2015, LIGO in the USA detected gravitational waves, ripples in space-time, from two black holes merging about 1.3 billion light-years away. This confirmed a prediction of Einstein's General Relativity made a century earlier. Weiss, Barish and Thorne won the 2017 Physics Nobel. Option (a) is wrong because the Higgs boson was found at CERN's Large Hadron Collider in 2012. Option (c) is wrong because wormholes remain theoretical. Option (d) is wrong because the observation did not explain the singularity at a black hole's centre.
Notice India's role: LIGO-India, approved in 2023, is being built at Hingoli, Maharashtra. Indian scientists also helped detect the GW250114 signal in 2025.
Answer as per the official UPSC answer key.
All years by topic
Every question from 2011 to 2026, grouped by syllabus topic, with year-wise trends.