UPSC Prelims Previous Year Questions 2022: Science & Technology | Science & Technology for UPSC CSE PDF Download

Ans: (d)

• The primary and secondary immune responses are carried out with the help of two special types(T cells) of lymphocytes present in our blood, i.e., B-lymphocytes (B cells) and T lymphocytes .
• The B-lymphocytes produce an army of proteins in response to pathogens into our blood to fight with them. These proteins are called antibodies. The T-cells themselves do not secrete antibodies but help B cells produce them.

Hence, option (d) is correct.

Ans: (d)

• Nanoparticles occur naturally in the environment in large volumes. They exist in the natural world and are also created as a result of human activities. Hence, statement 1 is NOT correct.
• The cosmetic industry is attaining the benefits of nanotechnology by developing nanoparticles for the enhanced performance and bioavailability of active components in cosmetics, sunscreens, anti-aging creams, moisturizers, and perfumes. The cosmetics are formulated by using different types of metal and metal oxide nanoparticles such as silver nanoparticles (AgNPs), gold nanoparticles (AuNPs) and titanium dioxide nanoparticles (TiO2 NPs), zinc oxide nanoparticles, (ZnO NPs), iron oxide nanoparticles, (Fe2O3 NPs) and carbon-based NPs [16–18].
  • The nanoparticles such as titanium dioxide (TiO2), zinc oxide (ZnO) are substantially used, since these nanoparticles are non-oily, easily absorbed.
  • TiO2 is essentially a UV filter (UVA and UVB filter) hence widely used in sunscreens and moisturizers as well. Hence, statement 2 is correct.
• Humans have evolved to cope with most naturally occurring nanoparticles. However, some nanoparticles, generated as a result of certain human activities such as tobacco smoking and fires, account for many premature deaths as a result of lung damage. Hence, statement 3 is correct.

Ans: (d)

• The novel technique of identifying biological specimens using short DNA sequences from either nuclear or organelle genomes is called DNA barcoding. DNA barcoding has many applications in various fields like preserving natural resources, protecting endangered species, controlling agriculture pests, identifying disease vectors, monitoring water quality, authentication of natural health products and identification of medicinal plants.
• Species identification of endangered wildlife (hence, distinguishes among species that look alike), quarantine pests, and disease vectors (identifying undesirable animals/plants) are just a few areas in which DNA barcoding is enabling researchers, enforcement agents, and consumers to make informed decisions in much shorter time frames.
• Statement 2 and statement 3 are correct, Hence, option (d) is correct (by elimination).

Ans: (b)

• Acid rain is a byproduct of a variety of human activities that emit the oxides of sulphur and nitrogen in the atmosphere. Burning of fossil fuels (which contain sulphur and nitrogenous matter) such as coal and oil in power stations and furnaces or petrol and diesel in motor engines produce sulphur dioxide and nitrogen oxides.
• SO₂ and NO₂ after oxidation and reaction with water are major contributors to acid rain, because polluted air usually contains particulate matter that catalyse the oxidation.
  2SO₂ (g) + O₂ (g) + 2H₂O (l) → 2H₂SO₄ (aq)
  4NO₂ (g) + O₂ (g)+ 2H₂O (l) → 4HNO₃ (aq)

Hence, option (b) is correct.

Ans: (a)

• Polyethylene terephthalate (PET or PETE), a strong, stiff synthetic fibre and resin and a member of the polyester family of polymers. PET is spun into fibres for permanent-press fabrics and blow-molded into disposable beverage bottles.
• They are often used in durable-press blends with other fibres such as rayon, wool, and cotton, reinforcing the inherent properties of those fibres while contributing to the ability of the fabric to recover from wrinkling.
• PET is the most widely recycled plastic PET bottles and containers are commonly melted down and spun into fibres for fibrefill or carpets. PET can be recycled into its original uses, and methods have been devised for breaking the polymer down into its chemical precursors for resynthesizing into PET.

Hence, option (a) is correct.

Ans: (d)

• Aarogya Setu has been transparent, privacy and security and in line with India’s policy on Open Source Software, the source code of Aarogya Setu has now been made open source.
• CoWin platform is being made open source, available to any and all countries. The Prime Minister, Shri Narendra Modi addressed the CoWin Global Conclave as India offered the CoWIN platform as a digital public good to the world to combat Covid-19. 
• DIKSHA (Digital Infrastructure for Knowledge Sharing) is a national platform for school education, an initiative of National Council for Education Research and Training (NCERT), Ministry of Education.
  • DIKSHA was developed based on the core principles of open architecture, open access, open licensing diversity, choice and autonomy as outlined in the Strategy and Approach Paper for the National Teacher Platform released by the former Hon’ Minister for Human Resources Development Shri Prakash Javdekar in May, 2017. 
  • DIKSHA itself was launched by the Hon’ Vice President of India on Sept 5th, 2017 and has since been adopted by 35 states/UTs across as well as CBSE and NCERT and by crores of learners and teachers. DIKSHA is built using Sunbird ED, a fully functional solution building block available as open-source software under MIT license and is part of Sunbird, a "Made in India, Made for the World" digital public good (DPG).
• DigiLocker isa key initiative under Digital India, the Government of India's flagship program aimed at transforming India into a digitally empowered society and knowledge economy. Targeted at the idea of paperless governance,
  • DigiLocker is a platform for issuance and verification of documents & certificates in a digital way, thus eliminating the use of physical documents.
  • The platform uses several open source technologies to deliver a mass solution and contributes back to the ever-growing community.

Hence, option (d) is correct.

Ans: (d)

Web 3.0:

• Web 3.0 is a decentralized internet to be run on blockchain technology, which would be different from the versions in use, Web 1.0 and Web 2.0. Hence statement 2 is correct.

Significance of Web 3.0:

• Decentralized and Fair Internet: Web3 will deliver a decentralized and fair internet where users control their own data. Hence statement 1 is correct. Eliminates Intermediaries: With block chain, the time and place of the transaction are recorded permanently.
• Thus, Web3 enables peer to peer (seller to buyer) transactions by eliminating the role of the intermediary. This concept can be extended to
• Decentralization and Transparency: The spirit of Web3 is Decentralized Autonomous Organization (DAO).
  • DAO is all about the business rules and governing rules in any transaction are transparently available for anyone to see and software will be written conforming to these rules.
  • With DAO, there is no need for a central authority to authenticate or validate.
• Web3, short for web 3.0, is a vision of the future of the Internet. It's operated by users collectively, rather than a corporation. Hence, statement 3 is correct.

Ans: (d)
SaaS is a method of software delivery that allows data to be accessed from any device with an internet connection and a web browser eg. mobile or computer. Hence statement 2 is correct.

• In this web-based model, software vendors host and maintain the servers, databases, and the code that makes up an application.
  • Users can customise the user interface and change data fields. Hence, statement 1 is correct.
• The common form of SaaS use is a web-based email service such as Outlook, Hotmail or Yahoo! Mail, with these services, you access your account over the Internet, often from a web browser. Hence, statement 3 is correct.

Ans: (c)
A Fractional Orbital Bombardment System (FOBS) is a warhead delivery system that uses a low earth orbit towards its target destination. Just before reaching the target, it deorbits through a retrograde engine burn.

• The Soviet Union first developed FOBS as a nuclear-weapons delivery system in the 1960s. It was one of the first Soviet efforts to use space to deliver nuclear weapons.

Hence, option (c) is correct.

Ans: (b)
Quantum computers compute in ‘qubits’ (or quantum bits). They exploit the properties of quantum mechanics, the science that governs how matter behaves on the atomic scale.
Hence, option (b) is correct.

Ans: (d)

Short Range Devices (SRD) are radio devices that offer a low risk of interference with other radio services, usually because their transmitted power, and hence their range, is low. The definition 'Short Range Device' may be applied to many different types of wireless equipment, including various forms of:

• Access control (including door and gate openers)
• Alarms and movement detectors

Closed-circuit television (CCTV)

• Cordless audio devices, including wireless microphones
• Industrial control

Local Area Networks

• Medical implants
• Metering devices
• Remote control

Radio frequency identification (RFID)

• Road Transport Telematics
• Telemetry.

Hence, option (d) is correct

Ans: (d)

• In medicine, biofilms form on medical implants and within human tissue as in cystic fibrosis; in industry they cover equip ment surfaces. Biofilms protect their inhabitants from various adverse environmental conditions including biocides and anti biotics. Hence, statement 1 is correct.
• Biofilms can form quickly in food industry environments. Particularities regarding attachment and composition of biofilms formed in food and food processing. Hence, statement 2 is correct.
  • Environments are presented and genes involved in biofilm production are mentioned.
• Microbial cells within biofilms have shown 10–1000 times more antibiotics resistance than the planktonic cells. Hence, statement 3 is correct.

Ans: (c)

• Probiotics are a combination of live beneficial bacteria and/or yeasts that naturally live in your body. Bacteria is usually viewed in a negative light as something that makes you sick. Hence, statement 1 is correct.
• Acidophilus is a probiotic bacteria that naturally occurs in the human gut and other parts of the body.This bacteria helps the digestive system break down sugars, such as lactose, into lactic acid. Trillions of bacteria and other micro-organisms live in every person's gut.
• There are several ways you can take a probiotic supplement. They come in a variety of forms, including in Foods,Drinks,Capsules or pills,Powders,Liquids. Hence, statement 2 is not correct but statement 3 is correct.

Ans: (b)

• COVISHIELD vaccine is based on the platform which uses a recombinant, replication- deficient chimpanzee adenovirus vector encoding the SARS-CoV-2 Spike (S) glycoprotein. Following administration, the genetic material of part of coronavirus is expressed which stimulates an immune response. Hence, statement 1 is not correct.
• Sputnik V is the world's first registered vaccine based on a well-studied human adenovirus vector platform. It has been approved for use in 71 countries with a total population of 4 billion people. The vaccine is named after the first Soviet space satellite. The vaccine’s efficacy is 97.6%, based on the analysis of data on the incidence of coronavirus among Russians vaccinated with both vaccine components between December 5, 2020 and March 31, 2021. Hence, statement 2 is correct.
• Covaxin is an inactivated viral vaccine. This vaccine is developed with Whole-Virion Inactivated Vero Cell-derived technology. They contain inactivated viruses, which cannot infect a person but still can teach the immune system to prepare a defence mechanism against the active virus. Hence, statement 3 is correct.

Ans: (c)

• The Sun emitted a strong solar flare on Tuesday, May 10, 2022, peaking at 9:55 a.m. EDT. NASA's Solar Dynamics Observatory, which watches the Sun constantly, captured an image of the event. Solar flares are powerful bursts of energy.
• The storms can often be observed as beautiful aurorae in our night sky, but they can also cause major disturbances in Earth’s power grids and navigation systems.
• A massive solar flare erupted from the Sun's surface, disrupting radio waves, telecommunication networks, and power systems by triggering an intense magnetic storm.
• Scientists have found evidence of an extreme solar 'tsunami' deep within the Earth's ice through analyses of ice cores from Greenland and Antarctica.
• A magnetic dam is formed which is storing a big mass of plasma. At the end of a solar cycle, this magnetic dam can break, releasing huge amounts of plasma cascading like a tsunami towards the poles.

Therefore, statements 1, 3, 4, 6 & 7 are correct. Hence option (c) is correct.

Ans: (b)
Paddy (Rice) is the most important anthropogenic source of both methane and nitrous oxide. Presently paddy production is facing major challenges which include scarcity of irrigation water and ongoing climate change. Modification of current cropping techniques can increase yields, save water and reduce greenhouse gas emissions.
Hence option (b) is correct.

Ans: (d)
The "Rice Intensification System" of agriculture, in which the paddy fields are alternately cleaved and dried, the main objective of this method is less requirement of seed, less production of methane and less consumption of electricity.
Hence option (d) is correct.