UPSC IAS Archives

1. In case of which one of the following biogeochemical cycles, the weath

In case of which one of the following biogeochemical cycles, the weathering of rocks is the main source of release of nutrient to enter the cycle?

Carbon cycle

Nitrogen cycle

Phosphorus cycle

Sulphur cycle

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UPSC IAS – 2021

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Option C is the correct answer. In the phosphorus cycle, the main reservoir of phosphorus is in rocks and minerals. Weathering of these rocks releases phosphorus into the soil and water.

The phosphorus cycle is unique among major biogeochemical cycles in that it does not have a significant atmospheric gaseous phase. The primary source of phosphorus for ecosystems is the slow weathering of phosphate-bearing rocks.

The carbon cycle involves atmospheric CO2, oceans, biomass, and fossil fuels. The nitrogen cycle primarily involves atmospheric nitrogen (N2) fixed by microbes, as well as organic matter decomposition. The sulphur cycle involves minerals (sulfates), atmospheric gases (SO2, H2S), and biological processes. While rocks can be a source in other cycles (e.g., sulfates in gypsum), rock weathering is the fundamental initial step that makes phosphorus available in most ecosystems.

2. Which one of the following is a filter feeder?

Which one of the following is a filter feeder?

Catfish

Octopus

Oyster

Pelican

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Option C is the correct answer. Oysters are filter feeders, meaning they obtain nutrition by filtering suspended food particles from water.

A filter feeder is an animal that feeds by straining suspended food particles from water. Examples include bivalve molluscs like clams and oysters, as well as some fish, whales, and birds.

Catfish are generally bottom feeders or predators. Octopuses are predatory cephalopods. Pelicans are birds that typically catch fish directly with their beaks, rather than filtering.

3. Magnetite particles, suspected to cause neurodegenerative problems, ar

Magnetite particles, suspected to cause neurodegenerative problems, are generated as environmental pollutants from which of the following?

1. Brakes of motor vehicles
2. Engines of motor vehicles
3. Microwave stoves within homes
4. Power plants
5. Telephone lines

Select the correct answer using the code given below.

1, 2, 3 and 5 only

1, 2 and 4 only

3, 4 and 5 only

1, 2, 3, 4 and 5

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Magnetite (Fe3O4) particles are a form of iron oxide that can be generated from various industrial and environmental processes, particularly those involving high temperatures or friction/wear of ferrous materials. Recent research has linked exposure to fine airborne magnetite particles to potential neurodegenerative health risks.
Let’s examine the potential sources:
1. Brakes of motor vehicles: Brake pads and rotors (often made of cast iron, rich in iron) undergo friction at high temperatures during braking. This process releases wear particles, a significant portion of which are iron oxides, including magnetite. This is a known source of airborne particulate matter in urban environments.
2. Engines of motor vehicles: Internal combustion engines operate at high temperatures, and combustion processes can produce various metal oxides as part of particulate emissions. Friction within the engine can also contribute wear particles. While complex, motor vehicle exhaust is a source of fine metallic particles.
3. Microwave stoves within homes: Microwave ovens heat food using electromagnetic radiation. They do not involve combustion or significant friction/wear in a manner that would generate airborne magnetite particles as an environmental pollutant.
4. Power plants: Combustion of fossil fuels (especially coal and heavy fuel oil) in power plants involves high temperatures and the burning of materials containing trace metals, including iron. Power plants are a significant source of various particulate emissions, including metal oxides like magnetite.
5. Telephone lines: Traditional copper telephone lines are made of copper, not iron. Modern fiber optic cables are made of glass/plastic. Neither involves processes that would generate airborne magnetite particles.
Based on the known sources of magnetite particles from combustion and friction/wear processes, brakes of motor vehicles, engines of motor vehicles, and power plants are plausible sources. Microwave stoves and telephone lines are not.

Airborne magnetite particles are often generated from high-temperature combustion or friction and wear involving iron-containing materials.

Other sources of environmental magnetite particles can include industrial processes like welding, mining activities, and even natural sources like soil dust (though anthropogenic sources are often more directly linked to neurodegenerative concerns). Research on the precise links between environmental magnetite exposure and neurodegenerative diseases like Alzheimer’s is ongoing but suggests a potential connection for ultra-fine particles entering the brain.

4. With reference to the New York Declaration on Forests’, which of the f

With reference to the New York Declaration on Forests’, which of the following statements are correct?

1. It was first endorsed at the United Nations Climate Summit in 2014.
2. It endorses a global timeline to end the loss of forests.
3. It is a legally binding international declaration.
4. It is endorsed by governments, big companies and indigenous communities.
5. India was one of the signatories at its inception.

Select the correct answer using the code given below.

1, 2 and 4

1, 3 and 5

3 and 4

2 and 5

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The New York Declaration on Forests (NYDF) is a non-legally binding political declaration that grew out of the 2014 UN Climate Summit. Let’s evaluate the statements:
1. It was first endorsed at the United Nations Climate Summit in 2014: This is correct. The declaration was launched and endorsed at the UN Climate Summit in New York in September 2014.
2. It endorses a global timeline to end the loss of forests: This is correct. The NYDF includes goals to halve the rate of loss of natural forests globally by 2020 and strive to end natural forest loss by 2030.
3. It is a legally binding international declaration: This is incorrect. The NYDF is explicitly a voluntary political declaration, not a legally binding treaty.
4. It is endorsed by governments, big companies and indigenous communities: This is correct. The NYDF is supported by a broad coalition of endorsers, including national and subnational governments, corporations, indigenous peoples’ organizations, and civil society groups.
5. India was one of the signatories at its inception: This is incorrect. While India participates in various international climate initiatives, India was not among the initial endorsers of the New York Declaration on Forests in 2014, nor has it become an endorser since.
Based on this, statements 1, 2, and 4 are correct.

The NYDF is a voluntary declaration launched at the 2014 UN Climate Summit with ambitious goals for reducing deforestation, supported by a wide range of actors, but is not legally binding and India is not a signatory.

The NYDF aims to mobilize action across all sectors to protect and restore forests as a key part of the climate solution and for sustainable development.

5. Consider the following animals : 1. Hedgehog 2. Marmot 3. Pangolin

Consider the following animals :

1. Hedgehog
2. Marmot
3. Pangolin

To reduce the chance of being captured by predators, which of the above organisms rolls up/roll up and protects/protect its/their vulnerable parts?

1 and 2

2 only

3 only

1 and 3

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Animals use various defense mechanisms against predators. Rolling up into a ball is a common defense strategy among certain species to protect their soft, vulnerable underbellies or heads.
1. Hedgehog: Hedgehogs are well-known for their ability to roll into a tight, spiny ball when threatened. Their strong back muscles allow them to pull their skin, covered in spines, over their head and legs, presenting a formidable defense.
2. Marmot: Marmots are large ground squirrels. Their primary defense mechanisms include loud alarm calls to alert others and retreating quickly into their burrows. They do not roll up into a ball for defense.
3. Pangolin: Pangolins are mammals covered in large, protective keratin scales. When threatened, they roll up into a tight ball, tucking their head under their tail and using their scales as armor against predators.
Therefore, both Hedgehogs and Pangolins employ the strategy of rolling up into a ball to protect themselves.

Hedgehogs use their spines and Pangolins use their scales as protection when rolling into a ball.

Other animals that roll up for defense include armadillos (some species), pill bugs (rolly pollies), and certain millipedes.

6. Consider the following kinds of organisms : 1. Copepods 2. Cyanobac

Consider the following kinds of organisms :

1. Copepods
2. Cyanobacteria
3. Diatoms
4. Foraminifera

Which of the above are primary producers in the food chains of oceans?

1 and 2

2 and 3

3 and 4

1 and 4

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Primary producers in any ecosystem are organisms that produce organic compounds from inorganic carbon sources, usually through photosynthesis. In the oceans, the primary producers are mainly phytoplankton, which are microscopic photosynthetic organisms.
1. Copepods: These are small crustaceans belonging to zooplankton. They are consumers, typically feeding on phytoplankton or other smaller zooplankton.
2. Cyanobacteria: Also known as blue-green algae, these are photosynthetic bacteria. They are significant primary producers in both freshwater and marine environments, contributing substantially to global oxygen production.
3. Diatoms: These are a major group of algae and are among the most common types of phytoplankton. They are responsible for a large percentage of the world’s oxygen production and are a primary food source in marine food chains.
4. Foraminifera: These are single-celled protists with shells. While some species host symbiotic algae (which are primary producers), Foraminifera themselves are heterotrophic, meaning they consume other organisms (like bacteria or algae) or detritus. They are consumers, not primary producers.
Therefore, Cyanobacteria and Diatoms are primary producers in ocean food chains.

Primary producers in the ocean are photosynthetic organisms, primarily phytoplankton like cyanobacteria and diatoms, which form the base of the marine food web.

Other important groups of marine primary producers include dinoflagellates, coccolithophores, green algae, and larger seaweeds (macroalgae) in coastal areas.

7. Which one of the following is used in preparing a natural mosquito

Which one of the following is used in preparing a natural mosquito repellent?

Congress grass

Elephant grass

Lemongrass

Nut grass

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Lemongrass (Cymbopogon species) is widely known for its natural mosquito repellent properties. It contains citronella oil, a volatile oil commonly used as an ingredient in mosquito repellents, candles, and lotions. The strong citrusy scent of lemongrass is effective in deterring mosquitoes and other insects.
– Congress grass (Parthenium hysterophorus) is an invasive weed notorious for causing allergies and has no repellent properties; in fact, it can be harmful.
– Elephant grass (Pennisetum purpureum) is a tall, fast-growing grass primarily used as fodder or for biomass energy; it is not used as a mosquito repellent.
– Nut grass (Cyperus rotundus) is a common weed with some traditional medicinal uses, but it is not widely known or used as a mosquito repellent.

Lemongrass contains citronella oil, a well-established natural insect repellent.

Other plants known for mosquito repellent properties include Citronella (closely related to lemongrass), Lemon Eucalyptus, Catnip, Basil, Lavender, and Peppermint.

8. Which one of the following is likely to be the most inflationary in it

Which one of the following is likely to be the most inflationary in its effects?

Repayment of public debt

Borrowing from the public to finance a budget deficit

Borrowing from the banks to finance a budget deficit

Creation of new money to finance a budget deficit

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Financing a budget deficit involves the government covering the gap between its spending and revenue. Different methods have different inflationary potentials:
A) Repayment of public debt: This is paying back outstanding loans. It injects liquidity into the economy but is not a method of financing a *deficit*.
B) Borrowing from the public: The government borrows existing savings from individuals and institutions. This transfers purchasing power from the public to the government, using existing money. It is generally considered the least inflationary method of deficit financing.
C) Borrowing from the banks: Banks can create credit based on their reserves. When the government borrows from banks, it can lead to an expansion of credit and money supply, which is more inflationary than borrowing from the public, but less so than creating new money.
D) Creation of new money (Monetizing the deficit): This involves the central bank directly financing the government deficit, essentially printing new money or crediting the government’s account without a corresponding withdrawal of purchasing power from the economy. This directly increases the money supply and is widely considered the most inflationary method of financing a deficit, as it adds fresh liquidity without increasing the supply of goods and services in the short term.

Financing a deficit by creating new money directly increases the money supply without withdrawing existing purchasing power, making it the most inflationary method compared to borrowing existing funds from the public or banks.

Excessive reliance on deficit monetization can lead to hyperinflation, as seen in several historical cases. Modern central banks often have legal restrictions on direct financing of government deficits to maintain price stability.

9. Which one of the following effects of creation of black money in India

Which one of the following effects of creation of black money in India has been the main cause of worry to the Government of India?

Diversion of resources to the purchase of real estate and investment in luxury housing

Investment in unproductive activities and purchase of precious stones, jewellery, gold, etc.

Large donations to political parties and growth of regionalism

Loss of revenue to the State Exchequer due to tax evasion

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Black money refers to income that has not been declared to the tax authorities and thus is untaxed. While black money has various negative effects on the economy and society, the primary concern for the government, from a fiscal and governance perspective, is the loss of revenue. Tax evasion, which is the mechanism by which black money is generated, directly reduces the tax base and the government’s ability to collect revenue. This loss of revenue restricts the government’s capacity to fund public services, infrastructure, and welfare programs, and can lead to higher fiscal deficits or increased borrowing. Other effects like diversion of resources, unproductive investments, and funding of political activities are significant negative consequences, but the fundamental issue from the state’s perspective is the direct drain on the exchequer due to tax avoidance.

Black money is essentially untaxed income. The most direct and significant impact of untaxed income for the government is the loss of tax revenue.

Other negative effects of black money include distortion of economic data, inflation (especially asset inflation in real estate and gold), increased inequality, corruption, and reduced effectiveness of monetary policy.

10. Consider the following statements: The effect of devaluation of a curr

Consider the following statements: The effect of devaluation of a currency is that it necessarily

1. improves the competitiveness of the domestic exports in the foreign markets
2. increases the foreign value of domestic currency
3. improves the trade balance

Which of the above statements is/are correct?

1 only

1 and 2

3 only

2 and 3

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Devaluation of a currency means reducing its value relative to other currencies.
1. Improves the competitiveness of domestic exports: When a currency is devalued, foreign buyers need less of their currency to buy goods from the devaluing country. This makes the domestic country’s exports cheaper in foreign markets, thus increasing their price competitiveness. This statement is generally true, assuming other factors like quality and supply capacity remain constant and demand is price-sensitive.
2. Increases the foreign value of domestic currency: This is incorrect. Devaluation by definition means the domestic currency is now worth *less* in terms of foreign currencies.
3. Improves the trade balance: Devaluation makes exports cheaper and imports more expensive. The *aim* is to increase exports and decrease imports, thereby improving the trade balance (reducing deficit or increasing surplus). However, this outcome is not *necessary*. The effect depends on factors like the price elasticity of demand for exports and imports (Marshall-Lerner condition), the time lag for these effects to materialize (J-curve effect), supply side constraints, and potential retaliatory measures by trade partners. Therefore, it does not *necessarily* improve the trade balance.
Only statement 1 is a necessary and direct consequence of devaluation in terms of price competitiveness.

Devaluation makes exports cheaper and imports more expensive in terms of domestic currency, directly impacting price competitiveness of exports. The impact on the trade balance is not guaranteed and depends on various economic factors.

The J-curve effect describes how a country’s trade balance may initially worsen following a devaluation or depreciation (because higher import prices outweigh increased export volumes) before eventually improving as trade volumes adjust.