Environmental issues practice · Mixed difficulty

Option B (Stratosphere) is correct because the ozone layer, which is being depleted, is located in the stratosphere.

Option D (Electrostatic precipitator) is correct because electrostatic precipitators are highly efficient in removing particulate matter from industrial emissions.

Option D (Enhance the need for chemical fertilisers) is correct because Ecosan toilets are designed to reduce the need for chemical fertilizers by recycling human excreta into natural fertilizers.

Option A (Carbon dioxide and water) is correct because catalytic converters oxidize unburnt hydrocarbons into carbon dioxide and water.

Option B (1987) is correct because the Montreal Protocol was signed in 1987 to address ozone depletion.

Option D (All of the above) is correct because decreased natural resources, increased urbanization, and increased population all contribute to desertification.

Option A (Radioactive wastes) is correct because both Three Mile Island and Chernobyl were nuclear disasters involving the release of radioactive materials.

Option A (Teeth) is correct because fluoride pollution primarily affects teeth, causing dental fluorosis.

The correct answer is not listed among the options. Chernobyl, Three Mile Island, and Bhopal were all industrial disasters, but Chernobyl and Three Mile Island were nuclear accidents, Love Canal was a chemical waste disaster, and Bhopal was a gas leak disaster. Therefore, none of the provided options accurately describe what all four had in common.

Option C (Microbes and organic matter) is correct because BOD (Biochemical Oxygen Demand) measures the amount of oxygen consumed by microbes while decomposing organic matter in water.

Option C is the incorrect statement because radiation from nuclear waste is harmful, not beneficial, to organisms.

Option D (I, II and III) is correct because all three statements accurately describe the advantages of CNG as a fuel.

The correct answer is C (1974 by Shri Sunder Lal Bahuguna) because the Chipko movement started in 1974 in Garhwal, Himalayas, led by Sunder Lal Bahuguna.

Option A is correct because the Chernobyl disaster is known to have caused leukaemia in exposed individuals, and radiation exposure is a known cause of leukaemia.

Option C (0.1) is correct because even a small percentage (0.1%) of impurities from domestic sewage can render water unfit for human use due to the presence of pathogens and pollutants.

Option B (1987) is correct because the Montreal Protocol, which aims to protect the ozone layer, was passed in 1987.

Option B ($S{O_2}$) is correct because scrubbers are primarily used to remove sulphur dioxide ($S{O_2}$) from exhaust gases by spraying water or lime.

Option A (CFCs) is correct because Chlorofluorocarbons (CFCs) are the primary cause of ozone layer depletion, leading to a reduction in the ozone umbrella's ability to protect us from UV rays.

Option B (Carbon monoxide) is correct because carbon monoxide is not a major contributor to the greenhouse effect compared to carbon dioxide, CFCs, and methane.

Option A (Montreal Protocol (Canada) in 1987 and effective in 1989) is correct because the Montreal Protocol is an international treaty designed to protect the ozone layer by phasing out the production and consumption of ozone-depleting substances.

Option D (Incineration) is correct because incineration is a combustion process that can convert gaseous pollutants into less harmful substances.

Option C (Kerala and Sri Lanka) is correct because ecological sanitation systems using dry composting toilets have been successfully implemented in Kerala, India, and Sri Lanka.

Option D is correct because organic farming relies on natural methods like manure and biofertilizers, and often utilizes resistant crop varieties to minimize synthetic inputs.

Option A (Montreal protocol) is correct because the Montreal Protocol is an international treaty designed to protect the ozone layer by phasing out the production and consumption of ozone-depleting substances like CFCs.

Option D ($\mathrm{HN}{\mathrm{O}_3}$) is correct because nitric acid is formed in the atmosphere from primary pollutants like nitrogen oxides.

Option C (Tribal methods of shifting cultivation) is correct because Jhum cultivation is a traditional agricultural practice used by some tribal communities involving clearing and cultivating land, then moving to a new area.

Option A (Reforestation) is correct because reforestation is the process of restoring forest cover in an area where it previously existed but was removed.

Option C (Radioactive fall out engulfed Bhopal) is correct because the Bhopal tragedy involved a gas leak, not a radioactive event.

Option C (Usnea (lichens)) is correct because lichens, particularly Usnea, are highly sensitive to sulfur dioxide (SO2) pollution and their presence or absence indicates air quality.

Option A (If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion) is correct because both the assertion that methane concentration has more than doubled and the reason that wetlands and rice fields are major sources of methane are true, and the reason explains the assertion.