UPSC Prelims Answer Key With Explanation 2019 – Paper 1 (General Studies)

Explanation

• Augmented reality (AR) is an interactive experience of a real-world environment where the objects that reside in the real-world are enhanced by computer-generated perceptual information, sometimes across multiple sensory modalities, including visual, auditory, haptic, somatosensory and olfactory. The overlaid sensory information can be constructive (i.e. additive to the natural environment), or destructive (i.e. masking of the natural environment). This experience is seamlessly interwoven with the physical world such that it is perceived as an immersive aspect of the real environment.In this way, augmented reality alters one’s ongoing perception of a real-world environment
• Virtual reality completely replaces the user’s real-world environment with a simulated one.
• https://en.wikipedia.org/wiki/Augmented_reality &
• https://en.wikipedia.org/wiki/Virtual_reality

Explanation

• Scientists have uncovered the most complete remains yet from the mysterious ancient-hominin group known as the Denisovans. The jawbone, discovered high on the Tibetan Plateau and dated to more than 160,000 years ago, is also the first Denisovan specimen found outside the Siberian cave in which the hominin was uncovered a decade ago confirming suspicions that Denisovans were more widespread than the fossil record currently suggests.
• The research marks the first time an ancient human has been identified solely through the analysis of proteins. With no usable DNA, scientists examined proteins in the specimen’s teeth, raising hopes that more fossils could be identified even when DNA is not preserved.
• Thus, Option B is Correct.

Explanation

Option (a)
Functional chromosomes can be created by joining segments of DNA taken from cells of different species is incorrect as it is functional DNA which can be created through recombinant DNA technology by joining DNA taken from different species.
https://www.nature.com/scitable/topicpage/recombinant-dna-technology-and-transgenic-animals

Option (b)
Pieces of artificial functional DNA can be created in laboratories.In 2007 Scientistsin Japan reported development of the world’s first DNA molecule made almost entirely of artificial parts. The finding opened up huge possibilities in gene therapy.
https://www.sciencedaily.com/releases/2008/07/080707091915.htm

Option (c)
A piece of DNA taken out from an animal cell can be made to replicate outside a living cell in a laboratory. It is exactly what is done through Polymerase chain reaction (PCR) technology.PCR mimics what happens in cells when DNA is copied (replicated) prior to cell division, but it is carried out in controlled conditions in a laboratory. The machine that is used is simply called a PCR machine or a thermocycler.
https://www.sciencelearn.org.nz/resources/2347-what-is-pcr

Option (d)
Cells taken out from plants and animals can be made to undergo cell division in laboratory petri dishes Plants cells are totipotent and a single cell has the potential to divide through mitosis in sterile conditions in a culture petridish to grow into a mature plant .Similarly animal cells can undergo mitotic cell division upto multicelled stages in a cultured petridishexamples: Somatic cell nuclear transfer technology(reproductive cloning) and Zygote created through Invitro fertilization.

Explanation

• A digital signature is a mathematical scheme for verifying the authenticity of digital messages or documents. A valid digital signature, where the prerequisites are satisfied, gives a recipient very strong reason to believe that the message was created by a known sender (authentication), and that the message was not altered in transit (integrity).
  https://en.wikipedia.org/wiki/Digital_signature

Explanation

• Wearable technology, wearables, fashion technology, tech togs, or fashion electronics are smart electronic
  devices (electronic device with micro-controllers) that can be incorporated into clothing or worn on the body
  as implants or accessories.
• Wearable devices such as activity trackers are an example of the Internet of Things, since “things” such as electronics, software, sensors, and connectivity are effectors that enable objects to exchange data (including data quality) through the internet with a manufacturer, operator, and/or other connected devices, without requiring human intervention.
• Wearable technology has a variety of applications which grows as the field itself expands. It appears prominently in consumer electronics with the popularization of the smartwatch and activity tracker. Apart from commercial uses, wearable technology is being incorporated into navigation systems, advanced textiles, and healthcare.
• https://en.wikipedia.org/wiki/Wearable_technology

Explanation

• RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression or translation, by neutralizing targeted mRNA molecules. RNAi is also known as post-transcriptional gene silencing (PTGS), and quelling.
• RNA interference (RNAi) is a promising gene regulatory approach in functional genomics that has significant impact on crop improvement. RNAi has also been exploited in plants for resistance against pathogens, insect/pest, nematodes, and virus that cause significant economic losses. This novel approach opens new avenues for crop improvement by developing disease resistant, abiotic or biotic stress tolerant, and high yielding elite varieties.
• RNA interference (RNAi) is a mechanism for gene silencing. Such mechanism possesses an unusual ability in targeting cancer-related genes.
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC309050/
  

Explanation

• Billions of light years away, two black holes have collided to create a larger one – the biggest black hole merger yet detected. It has a mass more than 80 times that of the sun.The resulting energy injected into the fabric of spacetime was also record breaking, with five sun’s worth of mass released in the form gravitational waves as the two holes spiralled in towards each other.Such titanic amounts of energy meant that the signal was still detectable by the time it reached gravitational wave detectors on Earth. It produced a recordbreaking result – the most distant collision detected so far, nine billion light years away.“This event also had black holes spinning the fastest of all mergers observed so far,” says the Australian National University’s Susan Scott, a chief investigator with the Centre of Excellence for Gravitational Wave Discovery (OzGrav). “It is also by far the most distant merger observed.”
  https://cosmosmagazine.com/space/gravitational-waves-biggest-black-hole-merger-ever-detected-revealed
  

Explanation

• The developing world where antibiotics can be bought for human or animal use without a prescription, the emergence and spread of resistance among bacteriahas been made worse. Thus in countries without standard treatment guidelines, antibiotics are often over-prescribed by health workers and veterinarians and over-used by the public.
• Without urgent action, the world is heading for a post-antibiotic era, in which common infections and minor injuries will once again lead to deaths like in the pre-antibiotic era.
• Genetic predisposition of people can make people more vulnerable to infections but it has nothing to do with increase in resistance to antibiotics in the micro-organisms.
• Multiple chronic diseases like diabetes,hypertension,cancer can increase the sufferers vulnerability to infections but it can not be the cause of multi-drug resistance.
  https://www.who.int/news-room/fact-sheets/detail/antibiotic-resistance 

Explanation
CRISPR Cas 9 is the latest genome editing tool with huge potential in gene therapy

• The CRISPR-Cas9 system consists of two key molecules that introduce a change (mutation?) into the DNA.
  These are:
• an enzyme? called Cas9. This acts as a pair of ‘molecular scissors’ that can cut the two strands of DNA at a specific location in the genome so that bits of DNA can then be added or removed.
• a piece of RNA? called guide RNA (gRNA). This consists of a small piece of pre-designed RNA sequence (about 20 bases long) located within a longer RNA scaffold. The scaffold part binds to DNA and the pre-designed sequence ‘guides’ Cas9 to the right part of the genome. This makes sure that the Cas9 enzyme cuts at the right point in the genome.
  https://www.yourgenome.org/facts/what-is-crispr-cas9

Explanation

• Hepatitis B, Hepatitis C and HIV are transmitted in a similar fashion through contaminated syringes, infectedblood, tranfusions, unprotected sexual intercourse.
• The number of people affected by Hepatitis B and C are much more than HIV infected people.
• People infected by Hepatitis B and C may remain symptom less for many years or with mild symptoms but the infection may manifest as chronic liver illness followed by Cirrhosis of liver and hepatic carcinoma.
• People can bevery effectively protected against Hepatitis B through vaccination. India is the largest producer of recombinant hepatitis B vaccine.There is no effective Hepatitis c vaccine till date.Efforts to develop a hepatitis C vaccine started more than 25 years ago, when the hepatitis C virus was identified. Since then, researchers have studied more than 20 potential vaccines in animals. A few of these vaccines, developed mainly in the past decade, have undergone limited testing in people.
• https://www.mayoclinic.org/diseases-conditions/hepatitis-c/expert-answers/hepatitis-c-vaccine/faq-20110002

Explanation

• Statement 1 is incorrect: High courts can strike down central laws also. For example Madras high court while disposing of a Writ petition seeking a declaration to the effect that the Pre-conception and Pre-natal Diagnostic Techniques (Prohibition of Sex Selection) (Six Months Training) Rules, 2014 declared it beyond the scope of the Pre-conceptional and Pre-natal Diagnostic Techniques (Prohibition of Sex Selection) Act, 1994, and inconsistent with Medical Council of India Act, 1956 and Regulations.
• Statement 2 is incorrect: The Supreme Court in Kesavananda Bharati case (1973) held that Constitutional amendment can be challenged on the ground that it violates a fundamental right that forms a part of the ‘basic structure’ of the Constitution and hence, can be declared as void. This was further reaffirmed in Golak Nath v.
  State of Punjab and Minerva Mill’s case. Therefore as it stands the constitutional amendment comes under a law for judicial review if it violates any fundamental rights and Basic structure of our constitution.
• Thus, Option D is correct.
  

The land reform legislations passed by Indian Government during 1950s were guided by following main objectives:

• Abolition of intermediaries.
• Tenancy reforms to regulate fair rent and provide security to tenure.
  
• Ceilings on holdings and distribution of surplus land among landless.
  
• Consolidation of holdings and prevention of their further fragmentation and
  
• Development of cooperative farming.

With reference to land reforms in independent India:

• Land Ceiling laws were applied to family holdings as well as individual holdings.
• The major aim of land reforms was providing agricultural land to all the landless.
• Land reforms were not connected to cultivation of cash crops in any way directly as a predominant form
  of cultivation.
• Land reforms permitted many exemptions to the ceiling limits such as for GARDEN LANDS, FOREST LAND AND BARREN LAND ETC.
• So statement ‘B’ is correct.
  

• The Global Competitiveness Report (GCR) is a yearly report published by the World Economic Forum (WEF).
• WEF’s GCR assesses competitiveness of countries to provide insight into drivers of their productivity and prosperity. GCR scores are calculated on basis of 12 categories called ‘pillars of competitiveness which covers both business and social indicators.
• It includes pillars such as institutions, infrastructure, health and primary education, labour market efficiency, financial market development, technological readiness and market size.
• Thus, Option C is Correct.
  

• Charter Act of 1813 expressly asserted the Crown’s sovereignty over British India. It ended the trade monopoly of the East India Company in India except for trade in tea and trade with China.
• The revenues of India came under the control of British Parliament clearly in 1858. This process started with Pits’ India act 1784.
  

• It contributed to the revival of the indigenous artisan crafts and industries because foreign goods were boycotted. National Council of Education (or NCE) was an organisation founded by Indian nationalists in Bengal in 1906 to promote science and technology as part of Swadeshi industrialisation movement. It established the Bengal National College and Bengal Institute which would later merge to form Jadavpur University.
  

• Chanhudaro (located in Sind), Kot Diji (located in Sind), and Desalpur (located in Gujarat) are Harappan sites.
• Sohgaura (located in U.P.) is a site of Mauryan Period. A copper plate inscription belonging to the reign of Chandragupta Maurya was found at this place.
  

• Kanaganahalli is a Buddhist site located in Gulbarga District in Karnataka, India.
• During the excavations (2000 to 2002) a stone sculptured slab bearing the name Ranyo Ashoka was found here.
• It is first such inscribed portrait of Ashoka. It was found at Kanaganahalliwas unearthed from the ruined Buddhist stupa.
  

• Mahayana Buddhism started deification or worship of Buddha. Mahayana monks were known as Bodhisattvas. They followed the path of Bodhisattvas.
• Image worship and rituals were introduced by Mahayanist in Buddhism.
  

• Forced labour (Vishti) became more common during Gupta period. It was considered a source of income for the state. It was kind of tax paid by people to state.