Science & Technology

Statement I is Correct: Axiom-4 is a private astronaut mission to the ISS specifically designed to carry out science and micro-gravity research payloads.

Statement II is Incorrect: Based on official classification, SpaDeX (Space Docking Experiment) is categorized as a technology demonstrator for autonomous docking; while it paves the way for a space station, it is not officially listed as a micro-gravity research mission in this context.

Statement III is Correct: Gaganyaan, India's flagship human spaceflight program, includes multiple payloads for micro-gravity experiments to be conducted by the Vyomanauts in low Earth orbit.

Note: After the release of the UPSC ANSWER KEY 2025, we have updated the correct answer to B.

Unmanned Aerial Vehicles (UAVs) are aircraft systems operated without a human pilot onboard. Their capabilities depend on design type (like fixed-wing, multirotor, or hybrid) and power source.

I. Vertical landing – Only VTOL and multirotor drones can do vertical landings. Fixed-wing UAVs cannot. II. Automated hovering – Only multirotor drones and advanced hybrids can hover. Fixed-wing UAVs cannot hover at all. III. Battery-only power – Not all UAVs use batteries. Larger ones may use fuel, hybrid, or solar power.

None of the statements are correct.

Statement I: Correct Rare earth elements like europium, terbium, and yttrium are essential in flat TV screens and monitors due to their role in producing vibrant colors and enhancing display quality.

Statement II: Correct These elements exhibit phosphorescence—absorbing energy and slowly emitting light—which is key to their use in color reproduction and brightness in displays.

Relationship: Statement II explains why rare earth elements are crucial in displays, confirming the reason behind Statement I.

Therefore, both statements are correct and related.

Alternative powertrain vehicles are those that do not use conventional petrol/diesel engines. Instead, they rely on clean energy sources like electricity or hydrogen.

* I. BEVs – Run fully on batteries and electric motors. * II. FCEVs – Use hydrogen to make electricity via a fuel cell. * III. FCEHVs – Combine hydrogen fuel cell + battery + electric motor.

All three are alternatives to traditional fuel vehicles.

Statement I: Correct *GAGAN is an Indian SBAS developed by ISRO and AAI to enhance GPS accuracy and integrity, crucial for aviation safety.*

Statement II: Correct *It improves GPS reliability and accuracy, enabling better air traffic management and safer, efficient navigation.*

Statement III: Incorrect *GAGAN's benefits extend beyond aviation to railways, roadways, maritime, agriculture, and disaster management.*

Correct Answer: Only Statements I and II are correct.

Monoclonal antibodies are lab-made proteins that target specific antigens and can be used to treat viral infections like Nipah virus.

* I. Man-made proteins – Created by cloning a single immune cell type. * II. Bind to specific antigens – Help stimulate or guide immune response. * III. Used in viral infections – Applied in treating infections like Nipah virus.

All three statements are correct.

Majorana 1 chip is linked to quantum computing and deep learning is part of machine learning, but AWS did not introduce the Majorana 1 chip.

* I. Majorana 1 chip – Expected to advance quantum computing. * II. AWS introducing Majorana 1 – Incorrect, it's a Microsoft project. * III. Deep learning – A subset of machine learning.

Only statements I and III are correct.

Statement I: Incorrect The National Rail Plan targets 2030 for a future-ready railway, not 2028.

Statement II: Incorrect Kavach is an indigenous Automatic Train Protection system developed under 'Make in India', not with Germany.

Statement III: Correct Kavach uses RFID tags on tracks in station sections to track train location and speed continuously.

Therefore, Statements I and II are incorrect, and Statement III is correct.

Coal gasification is a process that converts coal into syngas (a mixture of carbon monoxide, hydrogen, carbon dioxide, and water vapor). Syngas acts as a fundamental building block for the chemical industry.

I is correct: Syngas can be converted into Ethanol through various chemical pathways, including catalytic synthesis or fermentation.

II is incorrect: Nitroglycerine is produced through the nitration of glycerol. Glycerol is typically obtained from natural fats/oils or as a byproduct of biodiesel production, not from coal gasification.

III is correct: Coal gasification is a major source of hydrogen for producing Ammonia. This ammonia is then reacted with carbon dioxide (also a product of gasification) to produce Urea.

CL-20, HMX, and LLM-105 are chemical substances known for their use as high-energy explosives in military weapons.

* CL-20: A powerful explosive with high energy density. * HMX: A well-known military explosive used in various munitions. * LLM-105: A newer explosive with similar high performance.

All three are explosives used in military weapons.

Pair I: Dornier-228 : Maritime patrol aircraft — Correct Dornier-228 is used by Indian Navy & Coast Guard for maritime patrol and surveillance.

Pair II: IL-76 : Supersonic combat aircraft — Incorrect IL-76 is a heavy military transport aircraft, not supersonic or combat.

Pair III: C-17 Globemaster III : Military transport aircraft — Correct C-17 is a strategic military transport aircraft used by the Indian Air Force.

Therefore, only pairs I and III are correct.

In lithium-ion batteries, the cathode is typically made of materials that include Cobalt, Lithium, and Nickel, depending on the chemistry used.

* I. Cobalt: Used in cathodes like LCO and NMC. * II. Graphite: Used in the anode, not the cathode. * III. Lithium: Core element in cathode materials (like LCO, LFP). * IV. Nickel: Found in cathode types like NMC and NCA.

Three of the four are used in cathodes.

Alternatively, you can use mnemonic CoLiNi to remember Cathode forming materials.

Viruses can survive in oceans, infect bacteria, and alter host cell transcription.

Statement I: False. Viruses can survive in ocean waters, and marine viruses are highly abundant.

Statement II: False. Viruses can infect bacteria; for example, bacteriophages specifically infect bacteria.

Statement III: False. Viruses can alter host transcription and modify host gene expression.

None of the statements are correct.

Fuel Cell Electric Vehicles (FCEVs) powered by hydrogen generate electricity by combining hydrogen (H₂) with oxygen (O₂) in a fuel cell. This process produces electricity, heat, and the only exhaust emission is water vapour (H₂O), making hydrogen fuel cells zero-emission.

Metaverse: This term accurately describes a network of interconnected, persistent 3D virtual spaces.

Key characteristics of the metaverse often include:

* Interoperability: Users can move between different virtual worlds seamlessly.

* User-Generated Content: Users can create, own, and trade virtual assets.

* Social Interaction: The metaverse facilitates social experiences and interactions.

_Let's look at why the other options are incorrect:_

* Big data analytics: This involves analyzing large and complex datasets to uncover patterns and insights. It's not directly related to virtual worlds.

* Cryptography: This focuses on secure communication and data protection techniques. While relevant to security within a metaverse, it doesn't define the concept itself.

* Virtual matrix: This term is not commonly used to describe the concept outlined in the question. The term 'matrix' is often associated with a grid-like structure or a virtual reality environment, but not the broader interconnected network the question describes.

* Statement-I is incorrect: Giant stars do not live much longer than dwarf stars. In fact, giant stars have shorter lifespans compared to dwarf stars because they burn through their nuclear fuel at a much faster rate.

* Statement-II is correct: Compared to dwarf stars, giant stars have a greater rate of nuclear reactions. This is correct as giant stars are more massive and have higher pressures and temperatures in their cores, leading to faster nuclear fusion rates.

Statement 1 is correct: Hydrogels are widely used in biomedical applications, especially in controlled drug delivery systems. Their high water content, biocompatibility, and ability to swell and release drugs in a controlled manner make them ideal for:

- Transdermal drug delivery - Oral and ocular delivery - Injectable drug systems

Statement 2 is incorrect: Hydrogels are not commonly used in mobile air-conditioning systems. These systems typically use refrigerants and mechanical components (like compressors, condensers, and evaporators) to provide cooling. While hydrogels can absorb and release moisture, they are not suitable for the cooling and dehumidification processes involved in air conditioning.

Statement 3 is incorrect: Hydrogels are not used in the formulation of industrial lubricants. Lubricants generally consist of base oils (mineral, synthetic, or vegetable) and additives for enhancing properties like viscosity, anti-wear, and corrosion resistance. Hydrogels do not possess the required lubricating properties, especially under high pressure and temperature conditions.

Pumped-storage hydropower (PSH) is used for long-duration energy storage. It works by pumping water to a higher reservoir during low electricity demand and releasing it to generate power during peak demand. This process helps balance the grid supply and demand, making PSH an effective tool for energy storage over extended periods.

Thus, the correct answer is C.

* Statement 1 is incorrect: This is typically done using X-ray scanners or advanced imaging technologies like millimeter wave scanners, not traditional radar.

* Statement 2 is correct: Radars, specifically weather radars, are commonly used to monitor precipitation. They can detect rain, snow, and other weather conditions by bouncing radio waves off precipitation particles.

* Statement 3 is correct: Radars can be used to track the migration of birds and other animals. They are often used in ornithological studies to monitor bird migration patterns.

Distributed Energy Resources (DERs) are small-scale units of power generation or storage that are situated closer to the end-users. Let's analyze each option:

* Battery storage: These store energy and can be deployed within the distribution network or at the consumer end, making them DERs.

* Biomass generators: These can be small-scale and located near the biomass source, making them suitable for distributed generation.

* Fuel cells: Similar to biomass generators, fuel cells can be deployed in a decentralized manner, qualifying as DERs.

* Rooftop solar photovoltaic units: These are a classic example of DERs, generating power at the point of consumption.

_Therefore, all four options are considered Distributed Energy Resources._

* Statement 1: Incorrect. RTGs (Radioisotope Thermoelectric Generators) are not miniature fission reactors. Fission reactors use nuclear fission, a process of splitting atoms to release a tremendous amount of energy. RTGs, on the other hand, utilize the natural radioactive decay of isotopes to generate heat, which is then converted to electricity through a process called thermoelectricity.

* Statement 2: Correct. RTGs are indeed a reliable power source for spacecraft, especially those venturing far from the sun where solar panels become ineffective. They provide consistent, low-level electric power for extended periods, making them ideal for probes, satellites, and rovers in deep space.

* Statement 3: Correct. Plutonium-238 is a common isotope used in RTGs due to its long half-life (the time it takes for half of the material to decay) and its ability to generate a steady heat output from its decay process. While it can be a byproduct of weapons development, there are also alternative ways to produce Plutonium-238 specifically for peaceful applications like RTGs.

All three plants—Groundnut, Horse-gram, and Soybean—belong to the pea family, scientifically known as Leguminosae or Fabaceae. This family is characterized by plants that produce legumes (pods containing seeds). Here's a breakdown of each:

Groundnut (Arachis hypogaea):

* Groundnut, also known as peanut, belongs to the Leguminosae family. It produces peanuts, which grow underground in pods, typical of legumes.

* It is part of the subfamily Faboideae, a major division within the pea family.

Horse-gram (Macrotyloma uniflorum):

* Horse-gram is another plant in the Leguminosae family. It is commonly cultivated in tropical regions and is known for its high protein content and use in animal feed and food.

* It belongs to the subfamily Faboideae as well.

Soybean (Glycine max):

* Soybean, one of the most important leguminous crops, also belongs to the Leguminosae family. It is widely grown for its edible beans and oil extraction.

* Soybean is part of the subfamily Faboideae too.

All three plants are legumes, characterized by their pod-like fruit and ability to fix nitrogen from the atmosphere through a symbiotic relationship with bacteria in their root nodules.

Nitric oxide (NO) is synthesized in the human body by the enzyme nitric oxide synthase from the amino acid arginine. It plays a crucial role in dilating blood vessels, which increases blood flow and reduces blood pressure. This function helps in regulating cardiovascular health.

_Why the other options are incorrect:_

B. Nitrous oxide: Used as an anesthetic, not a vasodilator.

C. Nitrogen dioxide: A toxic air pollutant, not involved in vasodilation.

D. Nitrogen pentoxide: A reactive compound, not related to blood vessel dilation.

Fifth-generation fighter aircraft are characterized by advanced stealth, superior agility, advanced avionics, and integrated computer systems. Let's consider the aircraft listed:

1. Rafale: This is a 4.5 generation multirole fighter aircraft developed by Dassault Aviation.

2. MiG-29: This is a fourth-generation multirole fighter aircraft developed by Mikoyan in the Soviet Union.

3. Tejas MK-1: This is a fourth-generation light multirole fighter aircraft developed by Hindustan Aeronautics Limited (HAL) in India.

_None of the above aircraft are considered fifth-generation fighter aircraft._

* Car Crash Detection and Airbag Deployment: Modern cars use accelerometers as part of a complex system to detect rapid deceleration that can indicate a crash. The accelerometer data, along with other sensors, triggers the airbag deployment almost instantaneously.

* Laptop Fall Detection and Hard Drive Shut Off: Some laptops use accelerometers to detect a sudden fall or impact. This can trigger the hard drive heads to retract or park, protecting the drive from potential damage.

* Smartphone Tilt Detection and Display Rotation: Accelerometers are widely used in smartphones to detect orientation changes (tilt). This allows the device to automatically switch the display between portrait and landscape mode depending on how you hold the phone.

* In all these scenarios, the accelerometer detects changes in acceleration or tilt, which is then used by the system to perform the specific action.

Therefore, all three statements are correct.

* Pair 1 is incorrect: Cepheids are actually stars that brighten and dim periodically, not giant clouds of dust and gas.

* Pair 2 is incorrect: Nebulae are giant clouds of dust and gas in space, not stars that brighten and dim periodically. Thus, the first two pairs are reversed.

* Pair 3 is correct: Pulsars are rapidly rotating neutron stars that are formed when massive stars exhaust their fuel and collapse.

* So out of the 3 pairs given, only 1 pair (pair 3) is correctly matched.

* Microsatellite DNA, also known as short tandem repeats (STRs), are highly polymorphic DNA sequences that are widely used in the case of studying the evolutionary relationships among various species of fauna.

* Microsatellite DNA analysis is a powerful tool for studying genetic diversity, population structure, and evolutionary relationships among different species of animals.

* The variations in the number of repeated DNA sequences in microsatellites can provide insights into the genetic similarities and differences between species, which can be used to infer their evolutionary relationships.

Aerial metagenomics refers to the scientific technique of collecting and analyzing DNA samples directly from the air to identify the biological community present in a habitat.

* Metagenomics: This is the study of genetic material (genomes) recovered directly from environmental samples (like soil, water, or air). It bypasses the need for isolating and culturing individual species in a lab. * Environmental DNA (e-DNA): Organisms shed DNA into their surroundings through various means such as breath, skin, fur, or waste. This genetic material found in the environment is known as e-DNA. * Aerial Sampling: In 'Aerial' metagenomics, researchers use specialized filters or vacuum systems to capture this e-DNA from the air. This allows for the simultaneous monitoring of multiple species (animals, plants, fungi, and microbes) in a specific area at one go, providing a non-invasive way to track biodiversity.

Hence, option A is correct.

All four statements are correct.

* Medicinal mushrooms: Certain mushroom species have been used in traditional medicine for centuries and are still being studied for their potential health benefits. Examples include reishi mushrooms (Ganoderma lucidum) for immune system support and lion's mane mushrooms (Hericium erinaceus) for cognitive function.

* Psychoactive mushrooms: Some mushrooms contain psilocybin, a naturally occurring psychoactive compound that can induce hallucinations. These are commonly referred to as "magic mushrooms" or psilocybin mushrooms.

* Insecticidal mushrooms: Some mushroom species produce natural compounds that can repel or even kill insects. These compounds act as a defence mechanism for the mushrooms against insect pests.

* Bioluminescent mushrooms: A less common but fascinating property, bioluminescence, is found in some mushroom species. These mushrooms can produce and emit light, creating a glowing effect.

Statement 1 is Incorrect: Ballistic missiles are rocket-powered and follow a high, arcing trajectory, reaching supersonic speeds. In contrast, cruise missiles are jet-propelled, fly at lower altitudes, and can be subsonic, supersonic, or hypersonic. The statement incorrectly swaps their propulsion characteristics.

Statement 2 is Incorrect: Agni-V is a solid-fuelled Intercontinental Ballistic Missile (ICBM) with a range of over 5,000 km. BrahMos is a supersonic cruise missile developed jointly by India and Russia. The statement incorrectly swaps the types of these two missiles.