Environment & Ecology Mixed Quiz: Set 26

The correct answer is A, about 0.04 per cent. Carbon dioxide is a trace gas, roughly four hundredths of one per cent of dry air by volume, yet it is the source of all the carbon that photosynthesis fixes into food and the chief gas by which human activity is warming the planet. Option B is wrong because four per cent would be a hundred times the real figure; no atmosphere of that composition could support present life comfortably. Option C is wrong because twenty-one per cent is the share of oxygen. Option D is wrong because about nine tenths of one per cent is the share of argon, the commonest inert gas in air. Nitrogen at seventy-eight per cent and oxygen at twenty-one make up almost all of it.

The correct answer is B, Earthworm. The earthworm is called the farmer's friend because its work keeps soil fit for crops. As it burrows it loosens the soil and lets air and water reach the roots, and the castings it leaves behind are rich in nitrogen, phosphorus and potash, so the topsoil is steadily renewed. Charles Darwin called earthworms nature's ploughmen for this reason. Farmers use the same habit in vermicomposting, where species such as Eisenia fetida turn cattle dung and crop waste into fine manure within a few weeks. A is wrong because the cockroach is a household pest that spoils food and carries germs. C is wrong because the honey bee is useful as a pollinator and for honey, but the name friend of the farmer is not given to it. D is wrong because the housefly spreads diseases such as typhoid and cholera. Exam tip: earthworm, the farmer's friend and nature's plough, used in vermicompost.

The correct answer is C, Bonn. The permanent secretariat of the United Nations Convention to Combat Desertification has been based at Bonn in Germany since 1999, in the same United Nations campus that hosts the secretariat of the UNFCCC, which is a useful memory link because both are Rio Conventions with their secretariats in the same German city. A is wrong because Geneva hosts bodies such as the World Health Organization, the World Meteorological Organization, the World Trade Organization and the Intergovernmental Panel on Climate Change secretariat, but not the UNCCD. B is wrong because Nairobi is the headquarters of the United Nations Environment Programme and of UN-Habitat, a fact often mixed up with this one. D is wrong because Paris is where the Convention was adopted in 1994 and is the seat of UNESCO, but the Convention's working secretariat is not there.

The correct answer is B, Decibel. The decibel, written dB, is the unit in which the intensity level of sound is expressed, and it is named after Alexander Graham Bell. The scale is logarithmic, so every rise of 10 dB stands for a ten-fold rise in sound intensity; zero decibel is the threshold of hearing and about 120 to 130 decibel is the threshold of pain. For legal limits the A-weighted decibel is used because it follows the response of the human ear. A is wrong because the ohm is the unit of electrical resistance. C is wrong because the joule is the unit of work and energy, and although sound carries energy, its loudness is not reported in joule. D is wrong because the ampere is the unit of electric current. Candidates who confuse these pick an electrical unit instead of the acoustic one.

The correct answer is B, 55 dB(A). The Rules of 2000 lay down 55 decibel as the day-time limit and 45 decibel as the night-time limit for a residential area. Reading the full table across is the safest way to answer such questions: industrial 75 by day and 70 by night, commercial 65 and 55, residential 55 and 45, and silence zone 50 and 40. A is wrong because 45 decibel is the night-time limit for the same residential zone, and the swapping of day and night values is the usual trap. C is wrong because 65 decibel is the day-time limit for a commercial area. D is wrong because 75 decibel is the day-time limit for an industrial area, the highest of the four zones. Day runs from 6 a.m. to 10 p.m.

The correct answer is C, one tonne of carbon dioxide equivalent. The tonne is the standard trading unit in every carbon market, compliance or voluntary, and it is written as 1 tCO2e. The word equivalent matters: gases other than carbon dioxide are converted into carbon dioxide terms using their global warming potential, so a much smaller quantity of methane or nitrous oxide can earn one credit. A is wrong because a kilogram is far too small to be a market unit; no registry issues credits in kilograms. B is wrong for the same reason, and a hundred kilograms is simply a tenth of the real unit, a figure offered to catch a candidate who half-remembers the tonne. D is wrong because a thousand tonnes is the scale of a whole small project's annual saving, not of a single credit; a project of that size would be issued a thousand separate credits, which is exactly how buyers are able to purchase them in small lots.

The correct answer is C, Certified Emission Reductions, abbreviated CER, each equal to one tonne of carbon dioxide equivalent and issued only after an accredited third party verifies the saving. India hosted a very large number of such projects and was among the world's biggest sellers of CERs. A is wrong because Emission Reduction Units arise from Joint Implementation, where one developed country funds a project in another developed country, not in a developing one. B is wrong because Assigned Amount Units are the emission allowances handed to developed countries themselves under Article 17, traded directly between governments rather than earned by a project. D is wrong because Renewable Energy Certificates are an Indian domestic instrument that lets an obliged buyer meet its renewable purchase obligation without owning a generating plant; they measure electricity from renewable sources, not avoided greenhouse gas, and have no standing under the Kyoto Protocol.

The correct answer is D, Ecotone. An ecotone is the transition zone where two different ecosystems meet and mix, such as the belt between a grassland and a forest, an estuary between a river and the sea, or a mangrove strip between land and ocean. It holds species of both neighbouring communities along with a few of its own, so the number of species and their density are often higher in it. This crowding at the edge is called the edge effect, and species found only in such a belt are called edge species. A is wrong because the ecosphere means the whole living world of the earth taken together with its environment. B is wrong because ecoboundary is not a term used in ecology. C is wrong because ecotwin is not an ecological term either. Exam tip: tie ecotone to the edge effect, and keep ecotone, a zone, apart from ecocline, a gradual gradient.

The correct answer is B, nitrate. Roots take up nitrogen chiefly as the nitrate ion and to a smaller extent as ammonium; inside the plant the nitrate is reduced and built into amino acids, proteins and nucleic acids. Option A is wrong because the triple bond of nitrogen gas is too strong for a plant to break, which is the whole reason fixation by bacteria, lightning or industry is needed. Option C is wrong because nitrogen dioxide is a pollutant gas of the air that reaches soil only after dissolving in rain as nitrate. Option D is wrong because urea applied as fertiliser must first be hydrolysed to ammonia by the enzyme urease in the soil and then nitrified before most of it is taken up.

The correct answer is A, leguminous plants. Rhizobium is a bacterium that lives in a symbiotic relationship with legumes such as gram, pea, bean, groundnut and arhar, forming nodules on their roots in which it converts nitrogen gas into ammonia using the enzyme nitrogenase; this is why legumes are grown in rotation to restore soil nitrogen. Option B is wrong because cereals form no such nodules and depend on soil nitrate or on fertiliser. Option C is wrong because conifers are not nodulated by Rhizobium, though some non-legumes such as Alnus host a different bacterium, Frankia. Option D is wrong because mosses have no true roots and so no root nodules at all; some do associate loosely with cyanobacteria. Inside the nodule the pink pigment leghaemoglobin keeps oxygen away from nitrogenase, the enzyme that does the fixing.

The correct answer is D, Ramsar Convention on Wetlands. The Ramsar Convention was signed at Ramsar in Iran in 1971 and came into force in 1975, two decades before the Earth Summit, and its secretariat sits at Gland in Switzerland; it therefore has no connection with Rio. The three Rio Conventions are those that arose from the United Nations Conference on Environment and Development held at Rio de Janeiro in 1992. A is wrong as an answer because the UNFCCC was opened for signature at Rio in 1992 and entered into force in 1994. B is wrong as an answer because the Convention on Biological Diversity was also opened for signature at Rio in 1992 and entered into force in 1993. C is wrong as an answer because the UNCCD, although adopted at Paris in 1994, was mandated by Agenda 21 at Rio and is counted as the third Rio Convention.

The correct answer is C, the Prairies. The temperate grassland is the same biome the world over, short nutritious grass with almost no tree, but each continent gives it a local name, and the pairs are asked directly in examinations. In North America, across the central United States and the Canadian plains, it is called the Prairies, and so much of it has been ploughed for wheat that the region is known as the granary of the world. Option A is wrong because the Pampas is the temperate grassland of Argentina and Uruguay in South America, famous for cattle ranching. Option B is wrong because the Steppes form the vast grassland belt of Eurasia, running from Ukraine across Central Asia. Option D is wrong because the Veld is the grassland of the plateau of South Africa. Complete the set with the Downs of Australia and the Canterbury of New Zealand, and keep the tropical grasslands separate: the Savanna of Africa, the Llanos and Campos of South America.

The correct answer is B, 100 metres. The Rules define a silence zone as the area up to 100 metres around a hospital, an educational institution or a court, and such an area has to be declared by the competent authority. Inside it the limits are the strictest of the four zones, 50 decibel by day and 40 by night, and horns, drums, loudspeakers and firecrackers are not allowed. A is wrong because 50 is the decibel limit of the silence zone by day, not a distance, and the number is placed in the options to mislead. C is wrong because 200 metres has no place in these Rules. D is wrong because 500 metres is far wider than the Rules provide; the limit is deliberately kept small so that the zone can actually be enforced around a single building.

The correct answer is C, Water Conservation. Tarun Bharat Sangh works on water conservation, and its base is at Bhikampura in Alwar district of Rajasthan. Led by Rajendra Singh, known as the waterman of India, villagers of the area built and repaired thousands of johads, the traditional earthen check dams that hold rainwater and let it sink into the ground. Wells filled again, fields came back under crops and streams such as the Arvari, dry for years, began to flow, which is why the body is studied as a model of community-led water harvesting. Rajendra Singh received the Ramon Magsaysay Award in 2001 and the Stockholm Water Prize in 2015. A is wrong because women's groups are part of the work but not its field. B is wrong because fighting corruption is not its subject. D is wrong because it is not a tribal youth organisation, and Alwar is not a tribal belt. Exam tip: Tarun Bharat Sangh, Rajendra Singh, johads of Alwar and the revived Arvari river.

The correct answer is B, Article 6. It holds all the market machinery of the Paris Agreement: Article 6.2 lets two countries cooperate bilaterally and transfer Internationally Transferred Mitigation Outcomes with a corresponding adjustment so the same tonne is not counted twice, Article 6.4 establishes a centralised crediting mechanism supervised by a United Nations body as the successor to the Clean Development Mechanism, and Article 6.8 covers non-market approaches such as finance and technology transfer. A is wrong because Article 2 states the purpose of the agreement, including holding the temperature rise well below two degrees Celsius. C is wrong because Article 9 deals with climate finance from developed to developing countries. D is wrong because Article 14 provides for the global stocktake, the periodic review of collective progress. Note the coincidence candidates stumble on: Article 6 of the Kyoto Protocol is Joint Implementation, a different thing.

The correct answer is C, Garhwal Himalayas. The Chipko movement began in 1973 in the Garhwal Himalayas, in Chamoli district of what is now Uttarakhand, when villagers hugged trees to stop contractors from felling them. Its name comes from the Hindi word chipko, to cling. Chandi Prasad Bhatt led the first protest at Mandal village, Gaura Devi led the women of Reni village in 1974, and Sunderlal Bahuguna carried the message across the hills with the slogan that the soil, water and pure air are the real produce of a forest. The movement led to a fifteen-year ban on green felling above 1,000 metres in the Himalayan forests of Uttar Pradesh in 1980. Option A is wrong because Patna in Bihar has no link with it. Option B is wrong because Thrissur is in Kerala, far from the movement. Option D is wrong because Jammu was never its centre. Exam tip: Chipko 1973, Garhwal; Appiko 1983, Karnataka.

The correct answer is D, SDG 15. Sustainable Development Goal 15 is Life on Land, and target 15.3 commits countries to combat desertification, restore degraded land and soil including land affected by desertification, drought and floods, and strive to achieve a land degradation neutral world. Land Degradation Neutrality means that the amount of healthy and productive land stays stable or increases, because whatever is degraded is matched by an equal area restored. A is wrong because SDG 6 is Clean Water and Sanitation. B is wrong because SDG 13 is Climate Action, which is linked to land degradation through drought and carbon loss but does not carry the neutrality target. C is wrong because SDG 14 is Life Below Water and deals with oceans, seas and marine resources. Remembering the pair of goals 14 and 15 as water and land is the quickest way to avoid this trap.

The correct answer is B, a fall in the dissolved oxygen content. The solubility of a gas in water decreases as the temperature of the water rises, so hot water discharged from a power station holds less dissolved oxygen. The damage is doubled because the metabolic rate of fish and other aquatic animals roughly doubles for every ten degrees of warming, so their demand for oxygen rises just as the supply falls. A is wrong because it states the relation in reverse; only cold water is rich in dissolved oxygen, which is why cold mountain streams support trout. C is wrong because salinity is raised by evaporation or by saline effluent, not by waste heat as such. D is wrong because a sharp fall in pH is caused by acidic effluent or acid rain, not by thermal discharge.

The correct answer is C, COP26 in Glasgow, held in 2021, where India placed a five-part pledge known as the Panchamrit before the conference: 500 GW of non-fossil energy capacity by 2030, half its energy requirement from renewables by 2030, a cut of one billion tonnes in projected emissions by 2030, a 45 per cent fall in the emission intensity of its gross domestic product by 2030 over the 2005 level, and net zero by 2070. A is wrong because COP21 in 2015 produced the Paris Agreement itself, years before any Indian net zero date was named. B is wrong because COP24 in Poland in 2018 is remembered for the Paris rulebook on transparency and accounting. D is wrong because COP28 in 2023 is associated with the first global stocktake, the operationalisation of the Loss and Damage Fund and the call to transition away from fossil fuels, not with India's net zero announcement.

The correct answer is D, Shriganganagar - Hanumangarh. Sem is the local word for waterlogging with salt, and it hurts Sriganganagar and Hanumangarh the most because these districts lie in the command area of the Gang Canal and the Indira Gandhi Canal. Years of canal water spread by flood irrigation, without drains and over a hard layer below the soil, have raised the water table until it reaches the root zone. As the water stands and evaporates it leaves salt behind, white patches appear on the surface and yields fall. Lined channels, surface and sub-surface drains, sprinkler irrigation and the planting of eucalyptus are used against it. A is wrong because Bharatpur and Dhaulpur face flooding of a different kind in the eastern plain. B is wrong because Banswara and Dungarpur are hilly, high-rainfall tribal districts. C is wrong because Jalore and Sirohi face salinity of groundwater and drought. Exam tip: sem means canal-fed waterlogging, remember the Indira Gandhi Canal command.