ASKiIMAN™
NEXUS / 2023 / GS1
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UPSC 2023: Nexus 61—70

Unearthing the structural logic of the paper. [Set A]

Question 61

World Geography

Consider the following countries:

  1. Bulgaria
  2. Czech Republic
  3. Hungary
  4. Latvia
  5. Lithuania
  6. Romania

How many of the above-mentioned countries share a land border with Ukraine?

Official Verdict: (a) Only two

The Core Concept: Ukraine is bordered by Russia (East), Belarus (North), Poland, Slovakia, and Hungary (West), and Romania and Moldova (South). Bulgaria is separated from Ukraine by Romania/the Black Sea. The Czech Republic is separated by Slovakia. Latvia and Lithuania are Baltic states completely blocked off by Belarus. Only two listed countries touch Ukraine.

Tethered to: REALM 122 TO 140: Contemporary IR World Map

UKRAINE Hungary Romania Latvia/Lithuania (Blocked by Belarus) Bulgaria
Water Vapour (H₂O) Absorbed IR

Question 62

Climatology

With reference to the Earth's atmosphere, which one of the following statements is correct?

  • (a) The total amount of insolation received at the equator is roughly about 10 times of that received at the poles.
  • (b) Infrared rays constitute roughly two-thirds of insolation.
  • (c) Infrared waves are largely absorbed by water vapour that is concentrated in the lower atmosphere.
  • (d) Infrared waves are a part of visible spectrum...

Official Verdict: (c)

The Core Concept: Water vapor is the most abundant greenhouse gas in the lower troposphere. It acts like a thermal blanket, strongly absorbing long-wave Infrared (IR) radiation emitted by the Earth's surface (Option C is true). Equator insolation is only about 2.4 times that of the poles, not 10x. IR is invisible (not part of the visible spectrum) and constitutes roughly 49% of solar insolation, not two-thirds.

Tethered to: REALM 65: Heat Balance & Earth's Budget

Question 63

Biomes & Soils

Consider the following statements:

  • Statement-I: The soil in tropical rain forests is rich in nutrients.
  • Statement-II: The high temperature and moisture of tropical rain forests cause dead organic matter in the soil to decompose quickly.

Which one of the following is correct in respect of the above statements?

Official Verdict: (d) Statement-I is incorrect but Statement-II is correct

The Core Concept: A classic geographical paradox. Despite the lush, massive vegetation above ground, rainforest soil (often Laterite) is extremely nutrient-poor and highly acidic (Statement I is false). Why? Because the extreme heat and torrential rainfall cause any dead matter to decompose instantly (Statement II is true), and those nutrients are either immediately sucked up by the trees or washed away (leached) deep beyond root reach by the rain.

Tethered to: REALM 37: Tropical Rainforest Ecosystems

Leaching NUTRIENT POOR
WATER High Specific Heat Slow Change LAND Low Specific Heat Fast Change Winter contrast is actually higher!

Question 64

Thermodynamics of Earth

Consider the following statements:

  • Statement-I: The temperature contrast between continents and oceans is greater during summer than in winter.
  • Statement-II: The specific heat of water is more than that of land surface.

Which one of the following is correct in respect of the above statements?

Official Verdict: (d) Statement-I is incorrect but Statement-II is correct

The Core Concept: Water indeed takes much more energy to heat up and cool down than land (Statement II is true - High Specific Heat). However, the extreme temperature contrast actually happens in Winter, not Summer. In winter, continental landmasses (like Siberia or Canada) lose heat incredibly fast and drop to extreme sub-zero temperatures, while the adjacent oceans hold onto their heat, creating massive winter temperature gradients (Statement I is false).

Tethered to: REALM 66: Temperature Distribution

Question 65

Geophysics

Consider the following statements:

  1. In a seismograph, P waves are recorded earlier than S waves.
  2. In P waves, the individual particles vibrate to and fro in the direction of wave propagation whereas in S waves, the particles vibrate up and down at right angles to the direction of wave propagation.

Which of the statements given above is/are correct?

Official Verdict: (c) Both 1 and 2

The Core Concept: P-waves stand for "Primary" because they travel fastest and hit the seismograph first. They are compressional (longitudinal) waves, acting like an accordion (particles push and pull in the same direction the wave travels). S-waves are "Secondary" and slower. They are shear (transverse) waves, acting like a shaken rope (particles move up and down, perpendicular to the wave's path).

Tethered to: REALM 11: Seismic Waves

P-WAVE Push-Pull S-WAVE Up-Down
Sea Water Drought Area Private Co. ALL ARE FALSE Beware the word "None"

Question 66

Energy Infrastructure

With reference to coal-based thermal power plants in India, consider the following statements:

  1. None of them uses seawater.
  2. None of them is set up in water-stressed district.
  3. None of them is privately owned.

How many of the above statements are correct?

Official Verdict: (d) None

The Core Concept: Extreme keywords like "None" are usually traps in UPSC. 1: Coastal plants (like Mundra UMMP) heavily utilize desalinated seawater for cooling. 2: Many major plants (like Koradi or Tirora) are situated in notoriously water-stressed regions like Vidarbha, Maharashtra. 3: Corporate giants like Tata Power, Adani Power, and JSW Energy privately own massive chunks of India's thermal capacity. Every statement is false.

Tethered to: REALM 68: Coal

Question 67

Biotechnology

'Wolbachia method' is sometimes talked about with reference to which one of the following?

  • (a) Controlling the viral diseases spread by mosquitoes
  • (b) Converting crop residues into packing material
  • (c) Producing biodegradable plastics
  • (d) Producing biochar from thermochemical conversion of biomass

Official Verdict: (a) Controlling viral diseases...

The Core Concept: Aedes aegypti mosquitoes transmit deadly viruses like Dengue, Zika, and Chikungunya. Scientists discovered that infecting these mosquitoes with a harmless bacteria called Wolbachia acts like a vaccine for the mosquito—it physically blocks the Dengue virus from replicating inside them. When Wolbachia-infected mosquitoes are released, they breed and spread the bacteria, crashing the transmission of the disease to humans.

Tethered to: REALM 302: Vector-Borne Diseases

Wolbachia DENGUE
1. Basalt/Farms 2. Lime/Oceans CO₂ 3. Deep Mines GEOENGINEERING

Question 68

Climate Tech

Consider the following activities:

  1. Spreading finely ground basalt rock on farmlands extensively
  2. Increasing the alkalinity of oceans by adding lime
  3. Capturing carbon dioxide released by various industries and pumping it into abandoned subterranean mines...

How many of the above activities are often considered and discussed for carbon capture and sequestration?

Official Verdict: (c) All three

The Core Concept: These are all cutting-edge methods of Carbon Dioxide Removal (CDR). 1: "Enhanced Rock Weathering"—basalt reacts with CO2 in the rain/soil, trapping it as carbonate. 2: "Ocean Alkalinization"—adding lime reduces ocean acidity, allowing the sea to safely absorb more CO2 from the atmosphere. 3: "Geological Sequestration"—the classic CCS method of pumping liquefied CO2 deep underground into porous rock or old mines.

Tethered to: REALM 278: Carbon Capture & Climate Bio

Question 69

Genomics

'Aerial metagenomics' best refers to which one of the following situations?

  • (a) Collecting DNA samples from air in a habitat at one go
  • (b) Understanding the genetic makeup of avian species...
  • (c) Using air-borne devices to collect blood samples...
  • (d) Sending drones to inaccessible areas to collect plant and animal samples...

Official Verdict: (a) Collecting DNA samples from air...

The Core Concept: Animals constantly shed DNA into their environment (skin, hair, breath). This is called environmental DNA (eDNA). "Aerial metagenomics" involves running an air filter in a forest or habitat to suck in the floating eDNA, allowing scientists to sequence it and identify exactly which species live in that area without ever having to physically see or trap the animals.

Tethered to: REALM 235: Genomics & Proteomics

eDNA Air Filtration
AT AT AT Repeats (STR) Species A Species B

Question 70

Genetics

'Microsatellite DNA' is used in the case of which one of the following?

  • (a) Studying the evolutionary relationships among various species of fauna
  • (b) Stimulating 'stem cells' to transform...
  • (c) Promoting clonal propagation...
  • (d) Assessing the efficacy of drugs...

Official Verdict: (a) Studying evolutionary relationships...

The Core Concept: Microsatellites (also known as Short Tandem Repeats or STRs) are short segments of DNA where a specific motif (like "AT") is repeated several times. Because these sections mutate (change length) much faster than normal genes, they act as high-resolution genetic fingerprints. This makes them the primary tool used by geneticists for paternity testing, forensic DNA profiling, and tracing the evolutionary lineage and population genetics of different species.

Tethered to: REALM 136: Evolutionary Theory