UPSC Prelims 2021 Analysis

Explanation

Filter feeders are a subgroup of suspension-feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialised filtering structure.

Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish (including some sharks). Some birds, such as flamingos and certain species of duck, are also filter feeders. Filter feeders can play an important role in clarifying water, and are therefore considered ecosystem engineers. They are also important in bioaccumulation and, as a result, as indicator organisms. Oyster is one of the filter feeders.

Pearl Farming

• Pearls are the only gemstones in the world that come from a living creature. Mollusks such as oysters and mussels produce these precious jewels.
• Pearl culture practices are present in Gujarat, Maharashtra, Bihar, Odisha, Kerala, Rajasthan, Jharkhand, Goa, and Tripura.

Explanation

The Common Carbon Metric (CCM) is a protocol developed by the United Nations Environment Program's Sustainable Buildings & Climate Initiative (UNEP-SBCI) for measuring energy use and reporting greenhouse gas (GHG) emissions from building operations.

Its purpose is to support GHG emissions reductions through accurate measurement of energy efficiency. It is a universal method of measuring a building's carbon footprint and allows emissions from buildings around the world to be consistently assessed and compared.

Therefore, it is used for assessing the carbon footprint of building operations around the world.

Explanation

Hedgehogs are small mammals have a unique defense mechanism where they roll up into a tight ball, using their sharp spines as a form of protection against predators.

Marmots do not roll up to protect themselves. Instead, they typically rely on burrows and their ability to give warning calls to avoid predators.

Similar to hedgehogs, pangolins also roll up into a ball when threatened. They use their tough keratin scales as armor to protect their vulnerable parts.

Explanation

Bisphenol A (BPA) is a key component in the manufacture of polycarbonate plastics.

Polycarbonate plastics are a type of synthetic plastic material that is known to contain Bisphenol A (BPA) as a structural component.

BPA is used in the production of polycarbonate plastics, which are commonly used in various consumer products such as Water bottles, Food storage containers, Household electronics, Eyeglass lenses, Compact discs (CDs) and digital versatile discs (DVDs)

BPA has raised health concerns due to its potential to act as an endocrine disruptor, which can interfere with the body's hormonal system.

Explanation

"Blue Carbon" designates carbon that is fixed via coastal ocean ecosystems , rather than traditional land ecosystems, like forests .

Although the ocean's vegetated habitats cover less than 0.5% of the seabed, they are responsible for more than 50%, and potentially up to 70%, of all carbon storage in ocean sediments.

Explanation

The correct statements about the New York Declaration on Forests are

It was first endorsed at the United Nations Climate Summit in 2014. It does endorse a global timeline to end the loss of forests, aiming for significant reduction by 2020 and ending deforestation by 2030. It is endorsed by a multi-stakeholder group, including governments, companies (big and small), and indigenous communities. Incorrect statements

The New York Declaration on Forests is not a legally binding international declaration. It's a voluntary political declaration. The Declaration is currently endorsed by over 190 entities but it is not endorsed by India. Therefore, the correct answer is code (1, 2, 4)

Explanation

Detritivores These are organisms that feed on dead and decaying organic matter (detritus).

Earthworms They are classic detritivores, breaking down organic matter in soil and aiding in decomposition. Millipedes They feed on decaying leaves and other organic debris on the forest floor. Woodlice These small crustaceans are also detritivores, consuming decaying plant and animal matter.

Jellyfish While they might incidentally ingest some detritus while filtering water for food, they are primarily carnivores, feeding on plankton and small fish. Seahorses These are also not detritivores. They are carnivores, feeding on small shrimp, plankton, and other invertebrates.

Therefore, 1,3 and 5 are detritivores.

Explanation

Water efficiency of a crop refers to the amount of water required for its growth and development.

Among the options provided, Sugarcane requires the highest amount of water for its growth, making it the least water-efficient crop. It needs around 1800-2200 mm of water per season. On the other hand, Sunflower requires about 672.4 mm/season, Pearl Millet being a drought-tolerant crop requires around 350 mm/season, and Red gram uses about 250-400 mm/season of water.

Therefore, Sugarcane is the least water-efficient crop among the given options.

Explanation

Triclosan (sometimes abbreviated as TCS) is an antibacterial and antifungal agent present in some consumer products, including

• toothpaste,
• soaps,
• detergents,
• toys,
• surgical cleaning treatments.

Explanation

Hyderabad was indeed recognized as a Tree City of the World, but not by the UNCDF and Arbor Day Foundation together. The recognition comes from a joint program by the UN Food and Agriculture Organization (FAO) and the Arbor Day Foundation.

Hyderabad was selected as a 2020 Tree City of the World by the Arbor Day Foundation in recognition of the city's commitment to urban forestry, including growing and maintaining its urban forests.

Therefore, only the second statement is correct, and the first statement is incorrect.

Explanation

Statement 1 is correct. The Climate-Smart Village (CSV) approach is an initiative under the CCAFS program, which focuses on improving climate resilience in agriculture through research and innovation. CCAFS operates in multiple countries, including India, and works on sustainable farming practices, resource efficiency, and climate adaptation strategies in rural areas.

Statement 2 is correct. CCAFS is a global research initiative under the Consultative Group on International Agricultural Research (CGIAR), which is a network of international agricultural research organizations. However, CGIAR’s global headquarters is in Montpellier, France, making the statement factually accurate.

Statement 3 is correct. ICRISAT, based in Hyderabad, India, is a major research institute focusing on improving dryland agriculture. It is indeed one of the CGIAR’s 15 global research centers, working on climate resilience, crop improvement, and food security in semi-arid regions.

Explanation

Statement 1 is correct. Furnace oil is indeed a product of oil refineries. It is a dark viscous residual fuel obtained by blending heavier components of crude oil.

Statement 2 is correct. Furnace oil is widely used in industries like cement, steel, and textiles for power generation and heating. It is burned in boilers, furnaces, and engines to produce energy.

Statement 3 is correct. Furnace oil contains high sulfur content, and its combustion releases sulfur oxides (SOₓ), contributing to air pollution and acid rain.

Explanation

Permaculture farming indeed discourages monocultural practices, promoting biodiversity and the efficient use of available resources. On the other hand, conventional chemical farming often involves monoculture practices.

Conventional chemical farming can lead to an increase in soil salinity due to the heavy use of synthetic fertilizers and pesticides, while permaculture farming promotes soil health and does not contribute to soil salinity.

The practice of mulching, which involves covering the soil with organic material to conserve moisture, suppress weeds, and improve soil health, is an important aspect of permaculture farming, but it is not necessarily a key practice in conventional chemical farming.

The statement about conventional chemical farming being easily possible in semi-arid regions but permaculture farming not being so easily possible in such regions is not necessarily true. Permaculture farming can be adapted to various climates and environments, including semi-arid regions, by using appropriate design principles and techniques.

Explanation

The R2 Code of Practices is a tool available for promoting the adoption of environmentally responsible practices in the electronics recycling industry.

R2 stands for Responsible Recycling. The Code of Practices outlines a set of standards that electronics recyclers should follow to ensure responsible handling of electronic waste.

Explanation

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

Brakes of motor vehicles - The friction between brake pads and brake discs/drums can generate magnetite particles that are released into the environment. Engines of motor vehicles - The high-temperature combustion processes in vehicle engines can also produce magnetite particles as a byproduct. Power plants - The high-temperature industrial processes involved in power generation, such as coal-fired power plants, can lead to the release of magnetite particles into the environment.

The other options (3. Microwave stoves within homes and 5. Telephone lines) are not major sources of magnetite particle pollution.

Therefore, the correct answer is the combination of options 1, 2, and 4.

Explanation

The Phosphorus Cycle is unique among major biogeochemical cycles because it does not involve a gaseous phase. Instead, phosphorus primarily moves through the lithosphere (rocks), hydrosphere (water), and biosphere (organisms).

• Weathering of Rocks: The main source of phosphorus in this cycle comes from the weathering of phosphate-rich rocks. Over time, geological processes break down these rocks, releasing phosphate ions (PO₄³⁻) into the soil and water.

• Absorption by Plants: Plants absorb phosphorus from the soil, and it moves up the food chain as herbivores and carnivores consume plants and other organisms.

• Return to the Soil: When organisms die, decomposition releases phosphorus back into the environment, where it can re-enter the cycle.

• Carbon Cycle: The main source of carbon is atmospheric CO₂, released by respiration, combustion, and volcanic activity.

• Nitrogen Cycle: Nitrogen is primarily cycled through the atmosphere, with nitrogen fixation (by bacteria) being a key process.

• Sulphur Cycle: Sulfur is mainly released from volcanic eruptions, decaying organic matter, and fossil fuel combustion, rather than rock weathering.

Explanation

1. Incorrect While some carbon monoxide might be produced during the smelting process, it's unlikely to be in lethal quantities with proper emission controls.

2. Correct Copper slag, a byproduct of the smelting process, can contain heavy metals like lead, arsenic, and cadmium. Rainwater or acidic runoff can leach these metals from the slag, contaminating soil and water resources.

3. Correct Sulphur dioxide (SO2) is a major pollutant released during copper smelting, primarily from the burning of sulfur-containing fossil fuels used in the process. SO2 emissions contribute to acid rain and air pollution.

Explanation

Statement 1 is incorrect Copepods are a group of small crustaceans found in nearly every freshwater and saltwater habitat. Copepods are major secondary producers in the World Ocean.

Statement 2 is correct Diatom refers to any member of a large group comprising several genera of algae, specifically microalgae, found in the oceans, waterways and soils of the world. They are major primary producers in the food chains of oceans.

Statement 3 is correct Cyanobacteria, also known as Cyanophyta, are a phylum of Gram-negative bacteria that obtain energy via photosynthesis. They are major primary producers in the food chains of oceans.

Statement 4 is incorrect Foraminifera are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly an external shell of diverse forms and materials. They are the consumer.