[Answers with Explanation] UPSC prelims GS1 paper 2023

Q61. 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?

(a) Only two
(b)Only three
(c) Only four
(d)Only five

 Answer: (a)

Q62. With reference to 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 2/3rd 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 the visible spectrum of electromagnetic waves of solar radiation.

Answer: (c)

The insolation received at the surface varies from about 320 Watt/m2 in the tropics to about 70 Watt/m2 in the poles.
Insolation constitutes majorly optical rays. Infrared waves are largely absorbed by water vapour that is concentrated in the lower atmosphere.
Hence the statement is correct.
Infrared waves are not part of the visible spectrum of electromagnetic waves of solar radiation.

Q63. Consider the following statements:

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

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

(a) Both Statement I and Statement-II are correct and statement 2 is the correct explanation for statement one.
(b) Both Statement-I and Statement-II are correct and statement 2 is not the correct explanation for statement one.
(c) Statement-I is correct but Statement-II is incorrect.
(d) Statement-I is incorrect but Statement-II is correct.

Answer: (d)

The soil in the tropical rainforest is poor in nutrients due to intense leaching. These are known as Latosols.
The high temperature and moisture of tropical rainforests cause dead organic matter in the soil to decompose quickly. Decaying matter (dead wood and leaf litter) is processed so efficiently because of the abundance of decomposers including bacteria, fungi, and termites. These organisms take up nutrients, which are released as wastes when organisms die.
In addition, the minerals are leached away because the process of decomposition is very fast and minerals are released faster. Hence Statement II is correct.

Q64. 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.

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

(a) Both Statement I and Statement-II are correct and statement 2 is the correct explanation for statement one.
(b) Both Statement-I and Statement-II are correct and statement 2 is not the correct explanation for statement one.
(c) Statement-I is correct but Statement-II is incorrect.
(d) Statement-I is incorrect but Statement-II is correct.

Answer: (a)

Statement I :The heat capacity of the ocean is much greater than that of the atmosphere or the land. As a result, the ocean slowly warms in the summer, keeping air cool, and it slowly cools in winter, keeping the air warm. The temperature contrast between continents and oceans is greater during summer than in winter.

Statement II: The specific heat capacity of water is much greater than the land. The specific heat capacity is the amount of heat needed to raise the temperature of one gram of the substance by 1 degree. The specific heat capacity of water is much greater than the land because the relative density of water is much lower than that of the land surface. It means more heat is required to raise the temperature of one gram of water by 1 degree than one gram of land.

Q65. Consider the following statements:

1. In the 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, do particles vibrate up and down at right angles to the direction of wave propagation.

Which of the statements given above is/are correct?

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (c)

P-waves move faster and are the first to arrive at the surface.
P-waves vibrate parallel to the direction of the wave.
The direction of vibrations of S-waves is perpendicular to the wave direction in the vertical plane.

Q66 With reference to coal-based thermal power plants in India, consider the following statements:

1. None of them uses sea water.
2. None of them are set up in water stressed districts.
3. None of them is privately owned.

How many of the statements given above are correct?

(a) Only one
(b) Only Two
(c) All Three
(d) None

Answer: (d)

Seawater is a frequent supply of cooling water for power plants near the coast in India.
Several of the country’s thermal power plants are located in areas facing high water stress, a problem since these plants use water for cooling.
There are both privately and publicly owned coal-fired thermal power stations in India. Ex: Jindal Tamnar Thermal Power Plant.
Case Study: Coastal Gujarat Power Limited (CGPL) is a coal fired power plant which operates (24 × 7) at an “once-through system” based sea water circulation for power generation.

Q67. ‘Wolbachia’ method is sometimes talk about with reference to which one of the following?

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

Answer: (a)

Wolbachia are natural bacteria present in up to 60% of insect species, including some mosquitoes.
However, Wolbachia is not usually found in the Aedes aegypti mosquito, the primary species responsible for transmitting human viruses such as Zika, dengue, chikungunya and yellow fever.
When Aedes aegypti mosquitoes carry Wolbachia, the bacteria compete with viruses like dengue, Zika, chikungunya and yellow fever.
This makes it harder for viruses to reproduce inside the mosquitoes. And the mosquitoes are much less likely to spread viruses from person to person.

Q68. 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 in the form of carbonated waters.

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

(a) Only one
(b) Only Two
(c) All Three
(d)None

Answer: (c)

Spreading rock dust on farmland could suck billions of tonnes of carbon dioxide from the air. The chemical reactions that degrade the rock particles lock the greenhouse gas into carbonates. The rock dust approach, called enhanced rock weathering (ERW).
Increasing the alkalinity of oceans by adding lime which can increase the ocean’s capacity to absorb CO2 from the atmosphere and reduce ocean acidification.
Capturing carbon dioxide involves capturing carbon dioxide (CO2) at emission sources, transporting and then storing or burying it in a suitable deep, underground location.

Q69. ‘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 of habitat
(c) Using air-borne devices to collect blood samples from moving animals
(d) Sending drones to inaccessible areas to collect plant and animal samples from land surfaces and water bodies

Answer: (a)

Aerial metagenomics involves the collection and analysis of genetic material, particularly DNA, from the air in a specific habitat or environment.
It aims to capture and study the genetic material present in airborne particles such as microorganisms, pollen, fungal spores, and other biological components.
By collecting DNA samples from the air, researchers can gain insights into the biodiversity, microbial composition, and genetic diversity of a particular habitat.

Q70. ‘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 into diverse functional tissues
(c) Promoting clonal propagation of horticulture plants
(d) Assessing the efficacy of drugs by conducting series of drug trials in a population

Answer: (a)

Microsatellite DNA, also known as short tandem repeats (STRs), is commonly used in genetic studies, particularly in the field of population genetics and evolutionary biology.
Microsatellites are short, repetitive DNA sequences found in the genomes of many organisms.
They are highly variable, meaning they can differ in the number of repeats among individuals.
By analyzing microsatellite DNA, researchers can assess the genetic variation within and between populations, infer the relationships among individuals or species, and study patterns of gene flow, genetic diversity, and population structure.
Therefore, microsatellite DNA analysis is primarily utilized for studying the relationships among species of fauna.