UPSC Essentials brings to you its initiative of subject-wise quizzes. These quizzes are designed to help you revise some of the most important topics from the static part of the syllabus. Attempt today’s subject quiz on Science and Technology to check your progress.As we mark the 3rd anniversary of the UPSC Essentials magazine, we thank our readers for being part of this journey. Your trust, feedback and continued support have shaped the magazine and encouraged us to keep improving with every edition. Click Here to read the UPSC Essentials magazine for September 2026. Share your views and suggestions in the comment box or write to us at manas.srivastava@indianexpress.com.QUESTION 1With reference to the Impact basins over the lunar surface, consider the following statements:1. The impact basins are formed over the lunar surface due to asteroid or meteorite hits.2. There are no impact basins located along the southeastern hemisphere of the Moon.3. At present, the largest and oldest impact basin is known as the Copernicus Basin.How many of the statements given above are correct?(a) Only one(b) Only two(c) All three(d) NoneRelevance: The question tests understanding of lunar surface features, particularly the formation and significance of impact basins caused by major asteroid or meteorite impacts. It is relevant to Science and Technology, especially India’s space missions, planetary exploration and the study of the Moon’s geological history.ExplanationStory continues below this ad— For the first time, planetary scientists have confirmed the existence of a hidden impact crater on the lunar surface using mineralogical data obtained from Chandrayaan-1 and it could predate the oldest known impact craters on the moon. A team of researchers from the Physical Research Laboratory (PRL), Ahmedabad, have identified the Australe Basin, which had remained untraced as this ancient basin had suffered erosion along its rims making it extremely difficult even for modern-day imaging techniques to detect.— This new study, published in the The Planetary Science Journal, has now shed light on one such impact basin confirmed to be located along the southeastern hemisphere of the moon. It has distinct morphology and gravity signatures and some unique mineralogical compositions. Hence, statement 2 is not correct.— Scientists believe that there are approximately 300 impact basins present on the moon. Of these, only 74 have been detected so far. Impact basins are formed over the lunar surface due to various violent space activities, like asteroid or meteorite hits. These are large craters, often several hundreds of kilometres in diameters, and can have distinct outer rims. Due to the space hits, these craters are often found with remnants of volcanic activities. Hence, statement 1 is correct.— PRL scientists are also of the opinion that this basin could well be older than and largest and the oldest known South Pole Aitken Basin (formed over 4 billion years ago) on the Moon. Hence, statement 3 is not correct.Story continues below this ad— Moreover, the Australe Basin was found to be in a province characterized by 248 small basalt ponds arranged in a circular pattern unlike several of the previously known impact basins that are classified for their smooth and vast hardened lava surfaces.— There were 11 scientific payloads onboard the Chandrayaan-1. Of these, six were contributions from international space agencies including National Aeronautics Space Administration (NASA) and the European Space Agency. The mineralogy of the Australe Basin was detected using data gathered by the Moon Mineralogy Mapper of NASA. It is an imaging spectrometer that was designed to create the mineralogical map of the lunar surface. It operates between the 405 and 3000 nanometer wavelength range.Therefore, option (a) is the correct answer.QUESTION 2With reference to the Yudh Abhyas, consider the following statements:1. It is a biannual bilateral military exercise between India and the US.Story continues below this ad2. The 22nd edition of Yudh Abhyas was conducted in Alaska, US.3. The exercise aims to enhance both armies’ joint military capability to employ Integrated Battle Groups (IBGs) in mountainous and semi-mountainous terrain.Which of the statements given above is/are correct?(a) 1 and 3 only(b) 2 and 3 only(c) 1 only(d) 3 onlyRelevance: The question tests awareness of India–US defence cooperation through bilateral military exercises and their strategic significance. It is also relevant to International Relations and Security, particularly India’s defence partnerships, military exercises and preparedness for operations in mountainous terrain.Explanation— The Indian and US armies have begun their annual bilateral military exercise to improve their ability to conduct joint operations in difficult terrain, focusing on Integrated Battle Groups, infantry operations, drones, autonomous systems, and long-range precision fires. Hence, statement 1 is not correct.Story continues below this ad— The 22nd edition of Yudh Abhyas is underway at the Auli Foreign Training Node in Uttarakhand and the Mahajan Field Firing Range in Rajasthan’s Bikaner. Hence, statement 2 is not correct.— The Ministry of Defence said the exercise aims to enhance both armies’ joint military capability to employ Integrated Battle Groups (IBGs) in mountainous and semi-mountainous terrain, with an emphasis on infantry-dominated operations. Hence, statement 3 is correct.— “It will strengthen interoperability, facilitate exchanges of best operational practices and strengthen joint planning and execution,” the statement noted.Therefore, option (d) is the correct answer.QUESTION 3With reference to the Weaponisation of space, consider the following statements:Story continues below this ad1. The military use of outer space covers the ability to launch a missile from Earth to destroy enemy satellites or other space-based assets.2. Till now, no country has publicly admitted to deploying weapons in space.3. The ability to send weapons from space to destroy ground-based targets is not included in the weaponisation of space.Which one of the following conclusions based on the above statements is correct?(a) All three statements are correct.(b) There are two correct statements, that include statement 2.(c) There is only one correct statement.(d) There is no correct statement.Story continues below this adRelevance: The question tests conceptual understanding of weaponisation of outer space, including the distinction between space-based and Earth-based anti-satellite capabilities. It is relevant to Science and Technology and International Relations, particularly international space law, strategic stability and the governance of military activities in outer space.Explanation— The United States, on September 15, said it had active weapons deployed in space, the first such public admission by any country, sparking a fresh debate. The US did not reveal the nature of weapons deployed, or when they were deployed. Hence, statement 2 is not correct.— Although this is the first time a country has publicly admitted to deploying weapons in space, the capabilities to do so are neither new nor a revelation. The military use of outer space covers a wide variety of capabilities: the ability to launch a missile from Earth to destroy enemy satellites or other space-based assets, the ability to send weapons from space to destroy ground-based targets, or the use of space-based weapons to target space-based assets. It is not clear which of these categories the US’s newly-acknowledged weapons fall into. Hence, statement 1 is correct and statement 3 is not correct. Space weapon capabilities— But the weapons need not be “kinetic” — they need not necessarily be able to cause physical destruction of enemy targets. The ability to disrupt or jam the enemy’s communications between its space and Earth-based systems, or attack their cyber-networks, can also be extremely effective in a conflict situation.Story continues below this ad— The most open demonstrations of such capabilities have been the anti-satellite tests, in which countries send a missile to destroy a satellite in space. Four countries — the US, Russia, China and India — have demonstrated this. Although the countries targeted their own non-functional satellites during the tests, this ability to completely destroy any space-based asset happens to be the most dramatic use of weapons in space to date.Therefore, option (c) is the correct answer.QUESTION 4Which of the following best describes quantum entanglement?(a) A phenomenon in which two or more particles become interconnected, such that the state of one is linked to the state of another, regardless of the distance between them.(b) A phenomenon in which particles lose their quantum properties when they are separated by a measurable distance.(c) A process in which particles exchange energy continuously through physical contact to maintain identical states.(d) A phenomenon in which the state of a quantum particle can be determined with complete certainty before it is measured.Relevance: The question tests understanding of quantum entanglement, a fundamental concept in quantum mechanics and an important basis for emerging quantum technologies. It is relevant for understanding India’s and global advances in quantum technologies.Explanation— Scientists at the Quantum Information and Computing (QuIC) laboratory at Raman Research Institute in Bengaluru have demonstrated a novel way to increase the stability of the quantum states that enable computation in a quantum computer that can potentially improve the reliability and integrity of these calculations.— Unlike traditional computers that encode electric states into 0s and 1s to store and process information, quantum computers make use of the very unique, but counter-intuitive, properties of the quantum world to carry out calculations.— One of these happens to be “quantum entanglement,” a remarkable property of the quantum world in which two particles, after undergoing an interaction, get “linked” (or entangled) together in such a way that they begin to behave like one single system. Measuring certain properties of one reveals information about corresponding properties of the other, irrespective of the distance between the two.— Quantum entanglement is a phenomenon in which two or more particles become interconnected, such that the state of one is linked to the state of another, regardless of the distance between them.Therefore, option (a) is the correct answer.QUESTION 5The term ‘carrageenan’ was recently in the news. It refers to:(a) A natural sweetening compound, derived from brown seaweed, and used by food companies to improve the sweetness of beverages and dairy products.(b) A protein-based emulsifying agent, extracted from marine fish, and used by food companies to improve the texture and stability of processed foods.(c) A mineral-rich extract, obtained from green seaweed, and used by food companies as a preservative in frozen and packaged foods.(d) A thickening agent, derived from red seaweed, and used by food companies to make things like ice cream, flavoured milk, and paneer substitutes.Relevance: The question helps distinguish marine biological resources and their industrial applications, particularly the use of algae/seaweeds in the food industry. It is relevant to questions on biotechnology, food technology, marine resources and emerging applications of natural products.Explanation— The Food Safety and Standards Authority of India (FSSAI) has issued recall orders to two Food Business Operators (FBOs) following lab testing and evaluations that found adulterated coriander powder, and carrageenan — which was “found not satisfactory with respect to Cadmium.”— In a social media post, FSSAI wrote: “The Food Safety and Standards Authority of India (FSSAI) has issued recall orders to two Food Business Operators (FBOs) under the FSS Act, 2006, following lab testing and evaluations. Both FBOs are required to execute immediate market recalls in accordance with the FSS (Food Recall Procedure) Regulations, 2017.”— Kanikka Malhotra, Consultant Dietician & Diabetes Educator, says that pesticide residue doesn’t change how coriander powder looks, smells or tastes, so you genuinely can’t tell just by using your senses. According to her, coriander is a crop, so it can pick up pesticide residue during farming, especially if extra or non-approved pesticides are used, or if the crop is harvested too soon after spraying.— Carrageenan is nature’s thickening agent, derived from red seaweed, and used by food companies to make things like ice cream, flavoured milk, and paneer substitutes.Therefore, option (d) is the correct answer.Previous Daily Subject-Wise-QuizDaily Subject-wise quiz — History, Culture, and Social Issues (Week 163)Daily subject-wise quiz — Polity and Governance (Week 180)Daily subject-wise quiz — Science and Technology (Week 179)Daily subject-wise quiz — Economy (Week 179)Daily subject-wise quiz — Environment and Geography (Week 179)Daily subject-wise quiz – International Relations (Week 179)Subscribe to our UPSC newsletter and stay updated with the news cues from the past week.Stay updated with the latest UPSC articles by joining our Telegram channel – IndianExpress UPSC Hub, and follow us on Instagram and X