Science & Technology

Statement 1 is Correct: Hyperthermophiles are microorganisms that can thrive in temperatures above 100°C (the boiling point of water). For example, *Pyrolobus fumarii* is an archaeon that lives in hydrothermal vents at temperatures up to 113°C.

Statement 2 is Correct: Psychrophiles (or cryophiles) are extremophilic organisms capable of growth and reproduction in cold temperatures, often ranging from -20°C to +10°C, which is below the freezing point of water (0°C).

Statement 3 is Correct: Acidophiles are microorganisms that thrive in highly acidic environments. Extreme acidophiles, such as *Picrophilus oshimae*, can grow optimally at pH levels below 3, with some species surviving at pH levels near 0.

* Satellite navigation is based on the use of range measurements between navigational satellites and the user. Information about the satellite's coordinates is given to the user through a navigation signal. Range measurements are based on the calculation of the receiving signal time delay compared with the signals generated by the user equipment.

* Currently, there are four global systems viz., GPS from the USA, GLONASS from Russia, Galileo from the European Union, and BeiDou from China. In addition, there are two regional systems viz., NavIC from India and QZSS from Japan.

* Global navigation system caters to the users in the entire world, whereas the regional navigation system caters to the users in the limited service area.

Hence, option (D) is the correct answer.

* Carbon fibres are highly valued for their unique properties like strength, lightness, and stiffness. They are widely used in the manufacturing of various components in automobiles and aircraft to reduce weight and improve performance.

* Carbon Fiber Recycling: While traditional carbon fibre recycling methods were limited, advancements are being made in this field. Here are some possibilities

1. Mechanical recycling - This process breaks down carbon fibres into smaller pieces for use in applications where their original form is not necessary.

2. Chemical recycling -This method dissolves the resin holding the fibres together, potentially allowing the extraction of reusable carbon fibres.

3. Thermal recycling - High temperatures are used to convert the resin into usable materials while recovering the carbon fibres.

* These recycling technologies are still evolving, but they offer a more sustainable approach to using carbon fibres. Hence, statement 2 is incorrect.

The Wolbachia method is a biological method that utilises the Wolbachia bacteria to control the spread of mosquito-borne diseases, particularly dengue fever.

* Wolbachia naturally infects some insect species, but not Aedes aegypti mosquitoes, the primary vector for dengue fever transmission. Scientists introduce Wolbachia into Aedes aegypti populations. Wolbachia reduces the ability of these mosquitoes to transmit dengue virus.

* As Wolbachia spreads through the mosquito population, it can significantly reduce the incidence of dengue fever.

* This method offers a natural and sustainable approach to controlling dengue fever, a major public health concern in tropical and subtropical regions.

- A qubit is the fundamental unit of information in quantum computing, analogous to the bit in classical computing.

- However, unlike a bit that can only be either 0 or 1, a qubit can exist in a superposition of both states simultaneously.

- This property of qubits allows quantum computers to perform certain calculations much faster than traditional computers.

Statement 1 is correct. A key aspect of Web 3.0 is the concept of decentralization, where users have more control and ownership over their personal data, rather than having it stored and controlled by centralized platforms.

Statement 2 is correct. Blockchain technology is a core component of Web 3.0, and it can enable the creation of decentralized, user-owned social networks and platforms.

Statement 3 is correct. The decentralized nature of Web 3.0 means that it is not controlled by a single corporation or entity, but rather operated and maintained collectively by the users and participants in the network.

Therefore, all three statements regarding Web 3.0 are correct.


* Statement 1 is correct: Biofilms are a major concern in healthcare. They can form on implanted devices like catheters, heart valves, and artificial joints within human tissues. These biofilms can harbour bacteria that are difficult to eradicate with antibiotics, leading to chronic infections and potential implant failure.

* Statement 2 is correct: Biofilms can also form on food and food processing surfaces. This can contaminate food with bacteria and contribute to spoilage. Biofilms on these surfaces are also challenging to remove due to their protective matrix.

* Statement 3 is correct: Bacteria within biofilms can exhibit increased resistance to antibiotics. The biofilm matrix acts as a barrier, making it harder for antibiotics to reach and kill the bacteria. Additionally, bacteria within biofilms can communicate and share genetic material, potentially promoting the spread of antibiotic resistance genes.

All three statements are correct.

Statement 1 is correct. In many cases, Software as a Service (SaaS) providers allow some degree of customization of the user interface and data fields to meet the specific needs of their customers.

Statement 2 is correct. One of the key benefits of SaaS is its accessibility from anywhere with an internet connection, including mobile devices such as smartphones and tablets. SaaS applications are often designed to be mobile-friendly, allowing users to access their data and perform tasks on the go.

Statement 3 is correct. Outlook, Hotmail, and Yahoo! Mail are examples of web-based email services that operate on the SaaS model. Users access these email services through web browsers without needing to install or maintain any software locally on their devices. The email data is stored and managed remotely on servers operated by the service providers.

Therefore, all statements are correct.

It is a delivery system that uses a low Earth orbit to bypass early warning systems and deliver warheads on targets very quickly.

FOBS launches a warhead into a low Earth orbit trajectory instead of a full ballistic missile arc.

These systems are typically designed to detect missiles launched on high ballistic trajectories. A FOBS warhead in a low orbit might be harder to detect until it re-enters the atmosphere for its final approach to the target.

Due to the orbital path, the time between re-entry and target impact can be shorter compared to a traditional ballistic missile attack.

Statement 1 is incorrect. DNA Barcoding cannot assess the age DNA barcoding primarily focuses on identifying species based on their unique genetic sequences.

Statement 2 is correct. DNA barcoding is a valuable tool for distinguishing between species that appear similar morphologically. By analyzing short, standardized DNA sequences, scientists can efficiently and accurately identify different species, even if they look very alike.

Statement 3 is correct. DNA barcoding can be used to identify the origin and composition of food products. This can help detect cases where cheaper or undesirable ingredients (food adulteration) are substituted for the ones listed on the label. For example, it can be used to identify different types of meat in processed foods.

Therefore, statements 2 and 3 are correct.

Out of the listed communication technologies, all three can be considered short-range devices/technologies.

Closed-Circuit Television (CCTV): CCTV systems primarily use cables or wireless connections with a limited range, typically within a building or a designated area.

Radio Frequency Identification (RFID): RFID uses radio waves to identify objects. The reading range of RFID tags depends on the specific technology but generally falls within the short-range category, from a few centimetres to a few meters.

Wireless Local Area Network (WLAN): WLANs, commonly known as Wi-Fi networks, typically operate within a range of tens of meters indoors and up to hundreds of meters outdoors depending on factors like signal strength and frequency band. While the range might be slightly larger than the others on this list, WLANs still fall under the short-range classification compared to technologies like cellular networks or satellite communication.

B cells and T cells are both key components of the human immune system, which defend the body against harmful invaders like viruses, bacteria, and parasites.

B cells produce antibodies that can specifically target and neutralize pathogens.

T cells help orchestrate the immune response by directly attacking infected cells or by stimulating other immune cells.


Statement 1 is incorrect: Nanoparticles can exist in nature (natural nanoparticles). Volcanic eruptions, forest fires, and natural weathering processes can all create nanoparticles.

Statement 2 is correct: Some cosmetics incorporate nanoparticles of ingredients like zinc oxide or titanium dioxide for sun protection or other purposes.

Statement 3 is also correct: The safety of nanoparticles in consumer products is a complex issue and a growing area of research. Some nanoparticles might pose potential health or environmental risks depending on their specific properties and how they interact with the body or the environment.

- Ants are well-known as cultivators of fungi. Certain ant species, particularly those in the tribe Attini, have evolved a symbiotic relationship with specific fungi. These ants cultivate the fungus within their nests, providing it with food and a controlled environment. In return, the fungus provides the ants with nutrients. This is a fascinating example of mutualism in nature.

- Cockroaches are omnivores and scavengers. They do not cultivate fungi.

- Crabs are primarily scavengers or predators. They are not known to cultivate fungi.

- Spiders are predators and capture their prey (insects) in webs. They do not cultivate fungi.

Out of the listed effects of a major solar storm, the most likely ones are

Statement 1 is correct. A solar storm can disrupt the Earth's ionosphere, which can affect the signal transmission of GPS and other radio-based navigation systems.

Statement 3 is correct. Strong currents induced by the solar storm in power grids can damage transformers and cause widespread blackouts.

Statement 4 is correct. Solar storms can energize particles in the Earth's magnetosphere, leading to spectacular auroras at lower latitudes than usual.

Statement 6 is correct. The drag from a solar storm can alter the orbits of satellites, especially those in lower Earth orbit.

Statement 7 is correct. Similar to GPS, radio communication can be affected by disturbances in the ionosphere.

Statement 2 is incorrect. Tsunamis are caused by underwater earthquakes or volcanic eruptions, not solar storms.

Statement 5 is incorrect. While a solar storm could potentially ignite some fires through electrical sparks, this is not a widespread effect.

Therefore, codes 2 and 5 should not form the part of answer.

Statement 1 is Correct: Gucchi (Morchella esculenta) is a species of fungus belonging to the Morchellaceae family. It is highly prized for its honeycomb-like appearance and unique flavor.

Statement 2 is Correct: These mushrooms grow naturally in the temperate forest areas of the Himalayas, specifically in regions like Jammu and Kashmir, Himachal Pradesh, and Uttarakhand. They are typically found in conifer forests following the snowmelt.

Statement 3 is Incorrect: Gucchi mushrooms cannot be commercially cultivated on a large scale; they are wild-harvested by local communities. Furthermore, they are primarily associated with the Western Himalayas rather than north-eastern India.

Statement 1 is incorrect: Covishield, produced by the Serum Institute of India, is a viral vector vaccine. It uses a weakened chimpanzee adenovirus vector to carry genetic material from the SARS-CoV-2 virus into human cells.

Statement 2 is correct: Sputnik V is a vector-based vaccine, similar to Covishield. It uses two different human adenovirus vectors to deliver genetic material coding for SARS-CoV-2 spike proteins.

Statement 3 is correct: COVAXIN, developed by Bharat Biotech, is an inactivated virus vaccine. This means the SARS-CoV-2 virus used in the vaccine is inactivated (killed) so it cannot cause infection, but it still triggers an immune response.

Statement 1 is correct. Probiotics can be made from both bacteria and yeast. Some common probiotic strains include bacteria like Lactobacillus and Bifidobacterium, and yeasts like Saccharomyces boulardii.

Statement 2 is incorrect. The organisms in probiotics are naturally found in the human gut. We have a complex gut microbiome with trillions of bacteria and other microbes, some of which are beneficial. Probiotics are supposed to introduce specific strains of these beneficial microbes to improve gut health.

Statement 3 is correct. Probiotics might help with lactose digestion, but it depends. Lactose intolerance is caused by a lack of the enzyme lactase, which breaks down lactose (milk sugar) in the gut. Some probiotic strains might produce lactase, potentially aiding digestion in lactose-intolerant individuals.

The Lemongrass plant is known to be an excellent mosquito repellant.

According to a study conducted in 2011, around 95% of mosquitos from a specific range of species were either killed or completely repelled due to the intense odour of lemongrass oil.

Commonly known as Citronella oil, the impact of the essential oil from Lemongrass is known to last for around two and a half hours. For some species of mosquitos, it is even more.

Statement 1 is correct: The size of the hole in the lid regulates the amount of steam released. A larger hole permits more steam to escape, leading to reduced pressure and subsequently affecting the temperature.

Statement 2 is incorrect: Boiling water can never exceed 100 degrees Celsius, regardless of the intensity of the flame beneath the pot. However, within a pressure cooker, the temperature can elevate to as high as 121 degrees Celsius. The heightened cooking temperature serves to decrease the cooking duration rather than the temperature itself.

Statement 3 is correct: If the weight is heavier, it will require higher pressure to lift it, resulting in higher pressure inside the cooker before excess steam can escape. Higher pressure leads to a higher boiling point for the water inside the cooker, which in turn increases the cooking temperature. Conversely, if the weight is lighter, it results in a lower pressure inside the cooker and a lower boiling point for the water, leading to a lower cooking temperature.

Bollgard I and Bollgard II technologies are mentioned in the context of developing genetically modified (GM) cotton plants resistant to insect pests.

* Bollgard I: This was India's first commercially approved GM crop technology introduced in 2002. It incorporates a single gene (Cry1Ac) from the bacterium Bacillus thuringiensis (Bt) into cotton plants. This Bt gene produces an insecticidal protein that targets and kills certain insect pests, particularly the American Bollworm (Helicoverpa armigera).

* Bollgard II: This is a more advanced technology introduced in mid-2006. It incorporates two genes (Cry1Ac and Cry2Ab) from Bt into cotton. This provides broader resistance against a wider spectrum of insect pests, including lepidopteran caterpillars like the Spodoptera species, in addition to the American Bollworm.

Statement 1 is incorrect: Adenoviruses have double-stranded DNA genomes. Retroviruses have single-stranded RNA genomes.

Statement 2 is correct: Adenoviruses are one of the many viruses that can cause the common cold. AIDS (Acquired Immunodeficiency Syndrome) is caused by the Human Immunodeficiency Virus (HIV), which is a type of retrovirus.

Statement A is incorrect: The distance between stellar bodies does change, but often very slowly or in predictable orbits. Planets orbit stars, stars orbit galactic centers, and galaxies orbit each other, all causing continuous changes in distance. And this statement is not related to why distance is measured in light years.

Statement B is incorrect: While the gravitational constant is fundamental, the effective gravity of stellar bodies changes due to shifts in their mass (e.g., fusion, stellar winds), changes in their radius/size (expanding into red giants, collapsing into white dwarfs/neutron stars), and changes in the distance between them as they orbit. And this statement is not related to why distance is measured in light years.

Statement C is incorrect: Though mostly light travels in a straight line, it can be bent by Gravity- phenomenon known as Gravitational Lensing.

Statement D is correct: the speed of light does not change in a vacuum. So, it is a constant that can be used for measurement.

Water molecules are polar, meaning they have a positive charge on one end (the hydrogen atoms) and a negative charge on the other end (the oxygen atom). This polarity allows water molecules to attract and interact with other polar or charged molecules, facilitating the dissolution of a wide range of substances in water.

Therefore, option (a) is correct.

Fern: * Ferns typically require soil and moisture to grow, as they rely on water-conducting tissues and need a substrate to anchor their roots.

Lichen: * Lichens are a symbiotic association between a fungus and an algae or cyanobacteria. * Lichens are well-adapted to survive on surfaces without soil, such as rocks, tree bark, and even bare ground, as they can obtain their nutrients and moisture directly from the air and precipitation. * Lichens are sensitive to airborne pollutants, such as sulfur dioxide (SO2), nitrogen oxides (NOx), ozone (O3), and heavy metals (like lead and mercury). Sulfur dioxide, for instance, causes chlorosis (yellowing) and necrosis (cell death) in lichen thalli. This sensitivity makes lichens an effective indicator of air quality.

Moss: * Mosses are non-vascular plants that can grow on surfaces without soil, such as rocks, tree trunks, and even roofs. * Mosses have specialised structures that allow them to absorb water and nutrients directly from the environment.

Mushrooms: * Mushrooms are the reproductive structures of fungi, and they typically require a substrate, such as decaying organic matter, to grow. Mushrooms are not able to directly survive on a surface without soil or a nutrient-rich medium.

Therefore, among the given options, lichens and mosses are the most likely to be found surviving on a surface without soil in the natural environment.

* The term 'ACE2' is talked about in the context of the spread of viral diseases, particularly COVID-19.

* ACE2 stands for Angiotensin-Converting Enzyme 2. It's a protein found on the surface of many cell types in the human body, including those in the lungs, heart, kidneys, and intestines.

* Here's why ACE2 is significant:

* Receptor for SARS-CoV-2: The spike protein on the surface of the SARS-CoV-2 virus, the virus that causes COVID-19, binds to the ACE2 receptor in human cells. This binding is a critical step in the process of how the virus infects cells. * Multiple organ infection: Since ACE2 is expressed in various organs, it provides the virus with multiple potential entry points. This can contribute to the multi-organ complications sometimes associated with COVID-19. * Focus of research: Understanding the interaction between the virus and ACE2 is a major area of research for scientists developing vaccines and treatments for COVID-19.

Statement 1 is correct. Mitochondrial replacement therapy (MRT) is a reproductive technique used to prevent the transmission of mitochondrial diseases from mother to child. It involves replacing defective mitochondria in an egg or embryo with healthy mitochondria from a donor. MRT can be performed either before or after in vitro fertilization to ensure that the resulting embryo does not inherit mitochondrial diseases.

Statement 2 is correct. Mitochondrial DNA (mtDNA), which is responsible for encoding genes essential for mitochondrial function, is inherited exclusively from the mother. Therefore, mitochondrial diseases caused by mutations in mtDNA are passed down maternally, and a child cannot inherit mitochondrial diseases from the father.

Therefore, both statements are correct.

Statement 1 is Correct: Carbon nanotubes (CNTs) can be functionalized with various bioactive molecules, such as drugs and antigens. This allows them to act as efficient delivery systems that can cross biological membranes to reach specific target sites in the body.

Statement 2 is Incorrect: While carbon nanotubes have been explored as scaffolds in tissue engineering, their use as artificial blood capillaries remains largely experimental and has not been established as a validated application. Blood capillaries require precise biological compatibility, flexibility, and permeability that CNTs alone cannot replicate. Hence, the claim that they can be made into functional artificial blood capillaries for injured parts of the human body is not sufficiently supported, and UPSC's official answer key treats this statement as incorrect.

Statement 3 is Correct: Due to their high surface-to-volume ratio and unique electrical properties, carbon nanotubes are ideal components for biochemical sensors used to detect biological molecules like glucose, proteins, or DNA with high sensitivity.

Statement 4 is Correct: Research has demonstrated that carbon nanotubes can be broken down by oxidative enzymes such as myeloperoxidase (MPO) found in human neutrophils, establishing their biodegradability under certain conditions.

⚠️ Caveat: Statement 4 remains a subject of ongoing scientific debate. While certain studies confirm enzymatic biodegradation of CNTs, this is not universally accepted, as biodegradability is highly dependent on the type, length, surface functionalization, and structural properties of the nanotube. In many real-world conditions, CNTs are considered persistent and non-biodegradable. The UPSC answer key treats Statement 4 as correct, but candidates should be aware of this nuance.

In India, nuclear reactors are categorized into civilian and strategic (military) facilities as part of the 2005 Indo-US Civil Nuclear Deal. Reactors that rely on imported uranium are mandatory participants in the International Atomic Energy Agency (IAEA) safeguards to ensure the fuel is used strictly for peaceful, civilian purposes. In contrast, reactors using domestic uranium supplies are kept outside these safeguards to allow India the flexibility to use them for its strategic nuclear weapons program.



Statement 1 is correct. Plant cells have rigid cell walls made of cellulose, a complex carbohydrate, which animal cells lack. Animal cells rely on a plasma membrane for structure and protection.

Statement 2 is incorrect. Both plant and animal cells have a plasma membrane, a phospholipid bilayer that controls what enters and leaves the cell. It's a fundamental component for all cells.

Statement 3 is correct. Mature plant cells typically have a single, large central vacuole that stores water, nutrients, and waste products. Animal cells can have vacuoles, but they are usually smaller and more numerous.