[Answerkey] UPSC Prelims 2019 Science and Technology MCQ Solved


Science and Technology UPSC Prelims 2019 Answer Key

  • Many institutions have released their answer-keys. But here I have solved MCQs of Science and Tech part from UPSC Prelims 2019.
  • In this years papers almost 15 questions came from science and technology part. Most of them were current affairs based.
  • After running revision series for last 7 days I will cover topic wise solution of prelims question paper as I get time.
  • Disclaimer: Answers may not be correct and may not match bogus institutions answer keys. Also I may have left one or question here or there if you find one comment below.

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Ok now let us go through questions one by one.


Q3. In the context of proposals to the use of hydrogen-enriched CNG(H-CNG) as fuel for buses in public transport consider the following statements- Prelims 2019 Set B

  1. The main advantage of the use of H-CNG is the elimination of carbon monoxide emission
  2. H-CNG as a fuel reduces carbon dioxide and hydrocarbon emissions
  3. Hydrogen upto one fifth by volume can be blended with CNG as fuel for buses.
  4. H-CNG makes the fuel less expensive than CNG

Which of the statements given above is/are correct-

  1. 1 only
  2. 2 and 3 only
  3. 4 only
  4. 1, 2, 3 and 4

Look we know CNG is compressed natural gas right. Here we have HCNG it is nothing but H + CNG i.e. Hydrogen and CNG.

Now let us see options.

In the first option we have extreme keyword elimination. The fact is that H-CNG reduces CO by 70% but does not eliminate it totally so the option A and D gets eliminated. But option 2 is most likely to be correct so the answer is –> B.

Source: RSTV

Remote Sensing Satellites

Q12. For the measurement/estimation of which of the following are satellite images/Remote Sensing data used? Prelims 2019 Set B

  1. Chlorophyll content in the vegetation of a specific location
  2. Greenhouse gas emissions from rice paddies of a specific location
  3. land surface temperatures of a specific location.

Select the correct answer using the code given below

  1. 1 only
  2. 2 and 3 only
  3. 3 only
  4. 1, 2 and 3 Only.

Option 1 says about chlorophyll content of specific location. Now let us keep that aside for some time. In second statement we have green house gas emission tracking and in the last option we have surface temperature of a specific location.

Now by applying common sense, you may have seen those infrared maps showing temperature distributions right. Similarly green house gas emission is tracked with the help of satellite. So statement 2 and 3 are correct. Now we have eliminated option A and B as 2 and 3 are correct.

Regarding statement 1, remote sensing satellite can capture chlorophyll content in atolls and islands. See image below –

source: ResearchGate

Cirrus Cloud Thinning

Q45. In context of which of the following do some scientists suggest the use of cirrus cloud thinning technique and the injection of sulphate aerosol into stratosphere? Prelims 2019 Set B

  1. Creating the artificial rains in some regions
  2. Reducing the frequency and intensity of tropical cyclones
  3. Reducing the adverse effects of solar wind on the Earth
  4. Reducing the global warming

See either you know this or you don’t. If you have read newspaper carefully, it came in August 2017 edition of Hindu. Or either if you know that cirrus cloud cause global warming as they act as snow reflecting radiation back to earth. So thinning or removing then can reduce the global warming.

Q46. In the context of which one of the following are the terms pyrolysis and plasma gasification mentioned? Prelims 2019 Set B

  1. Extraction of rare earth elements
  2. Natural gas extraction techniques
  3. Hydrogen fuel-based automobiles
  4. Waste-to-energy technologies
  • The Hindu –> pyrolysis process converts waste into bio-oil

[AR vs VR] Augmented Reality vs Virtual Reality

Q51. In context of digital technologies for entertainment, consider the following statements – Prelims 2019 Set B

  1. in Augmented reality simulated environment is created and the physical world is completely shut out
  2. in virtual reality images generated from a computer are projected onto real life objects or surroundings
  3. AR allows individuals to be present in the world and improves the experience using the camera of smartphone on PC
  4. VR closes the world and transposition individual providing complete immersion experience

Which of the statements given above is/are correct-

  1. 1 and 2 only
  2. 3 and 4
  3. 1, 2 and 3
  4. 4 only
  • Augmented reality –> ex. the game of Pokemon
  • Virtual reality –> When we use VR headset. We shut down ourself from the world.

See the image below to get the difference.


Q52. The word Densiovan is sometimes mentioned in media is reference to – Prelims (2019 Set B)

  1. Fossil of a kind of dinosaurs
  2. An early human species
  3. A cave system found in the NE India
  4. A geological period in the history of Indian subcontinent

The Hindu –> 1st May 2019 Denisovans lived in the Tibetan Plateau

Q53. With reference to the recent developments in science, which one of the following statements is NOT correct? Prelims 2019 Set B

  1. Functional chromosomes can be created by joining segments of DNA taken from cells of different species
  2. Pieces of artificial functional DNA can be created in laboratories
  3. A piece of DNA taken out from an animal cell can be made to replicate outside a living cell in laboratory
  4. Cells taken out from plants and animals can be made to undergo cell division in laboratory petri dishes
  • Difficult question either you know it or you don’t
  • Statement B DNA Printing  –> creating artificial genes in laboratory
  • Statement C is cloning. Replicating with one individual.
  • last statement is about tissue culture

Q54. Consider the following statements – 

A digital signature is –

  1. an electronic record that identifies the certifying authority issuing it
  2. used to serve as proof of identity of an individual to access information or server on internet
  3. an electronic method of signing an electronic document and ensuring that the original content is unchanged

Which of the statements given above is/are correct?

  1. 1 only
  2. 2 and 3 only
  3. 3 only
  4. 1,2 and 3

Digital signature is electronic code or sign to ensure the authenticity of document.

Q55. In the context of wearable technology, which of the following tasks is/are accomplished by wearable devices? Prelims 2019 Set B

  1. Location identification of a person
  2. Sleep monitoring of a person
  3. Assisting the hearing impaired person

Select the correct answer using the code given below –

  1. 1 only
  2. 2 and 3 only
  3. 3 only
  4. 1,2 and 3

Here no need to dive in sources. Just use your logic. Wearable technology means wearable that can do the task of tracking. So location tracking, sleep tracking is correct. Ultimately last statement has to be correct.

Q56. RNA interference technology has gained popularity in the last few years. Why?

  1. It is used in developing gene silencing therapies
  2. It can be used in developing therapies for the treatment of cancer
  3. It can be used to develop hormone replacement therapies
  4. It can be used to produce crop plants that are resistant to viral pathogens

Select the correct answer using the code given below –

  1. 1, 2 and 4
  2. 2 and 3
  3. 1 and 3 only
  4. 1 and 4 only

Q57. Recently, scientists observed the merger of giant blackholes billions of light years away from the earth. What is the significance of this observation?

  1. Higgs boson particles were detected
  2. Gravitational waves were detected
  3. Possibility of intergalactic space travel through wormhole was confirmed
  4. It enabled the scientists to understand singularity

Gravitational waves –> Old topic but continuously in news. There was editorial on gravitational waves in The Hindu in November 2018. When two black wholes merged it created ripples in time space fabric which were detected by LIGO.

Q. Which of the following are the reasons for the occurrence of multi drug resistance in microbial pathogens in India?

  1. Genetic predisposition of some people
  2. Taking incorrect doses of some antibiotics to cure diseases
  3. Using antibiotics in livestock farming
  4. Multiple chronic disease in some people

Select the correct answer using the code given below –

  1. 1 and 2
  2. 2 and 3 only
  3. 1, 3 and 4
  4. 2, 3 and 4
  • 1st statement is wrong, AMR and genetic disposition (weakness) are not linked as such.
  • So answer is B or D and B is most probable answer. I will explain this in video.

[Cas9 Biotechnology] UPSC Prelims 2019

Q59. What is Cas9 protein that is often mentioned in news?

  1. A molecular scissors used in gene editing
  2. A biosensor used in the accurate detection of pathogens in patients
  3. A gene that makes plants pest resistant
  4. A herbicidal substance synthesised in genetically modified crops

It is CRISPR associated with protein 9 i.e. CRISPR + Protein 9 = Cas9. It has evolved as favourite topic of UPSC. Read more here.

[Hepatitis B Vaccine] Prelims 2019

Q60. Which one of the following statements is NOT correct?

  1. Hepatitis B virus is transmitted much like HIV
  2. Hepatitis B unlike Hepatitis C does not have a vaccine
  3. Globally, the number of people infected with Hepatitis B and C viruses are several times more than those infected with HIV
  4. Some of those infected with Hepatitis B and C viruses do not show the symptoms for many years


[VoLTE vs LTE] UPSC CSE Prelims 2019

Q95. With reference to communication technologies, what is/are the difference/differences between LTE (Long Term Evolution) and VoLTE (Voice over Long Term Evolution)

  1. LTE is commonly marketed as 3G and VOLTE is commonly marketed as advanced 3G
  2. LTE is data only technology and VoLTE us voice over technology.

Select the correct answer using the code given below.

  1. 1 only
  2. 2 only
  3. Both 1 and 2
  4. Neither 1 nor 2
  • Long term evolution
  • Carries data
  • No support to voice transmission
  • Quality of voice reduces when data is on
  • Voice over Long Term Evolution
  • Carry both voice and data
  • Voice as well as data transmission
  • Excellent quality of voice

As I said earlier, I may have left one or question here or there if you find one comment below. I will cover them in upcoming post.