Bihar Board Class 12 (Science) Environmental Issues — practice questions
73 free MCQs with worked solutions. Tap any question for the answer + explanation, or practice them all in the app.
Practice Bihar Board Class 12 (Science) Environmental Issues in the app →Which of these is a terrestrial ecosystem?Which is a man-made ecosystem?The basic energy input to any ecosystem is:Green plants in an ecosystem are called:Animals that feed directly on plants are:Producers belong to which trophic level?Energy movement through trophic levels is:The rate of biomass production is called:GPP minus respiration losses equals:The rate at which consumers form new organic matter is:The annual net primary productivity of the biosphere is about:Raw material for decomposition is called:Which is NOT a step of decomposition?Plants capture what share of photosynthetically active radiation?Decomposition is slower when detritus is rich in:Which conditions favour decomposition?The mass of living material at a trophic level is the:The pyramid of biomass in the sea is generally:Which ecological pyramid can never be inverted?Which group is left out of ecological pyramids?Biomagnification refers to a pollutant becoming more concentrated at what point?Which chemical is a classic example of a substance that biomagnifies?In which body tissue does DDT accumulate progressively?Many chemicals that biomagnify are highly soluble in which medium?Which form of mercury is among the most harmful and is absorbed by algae?The decline of predatory birds like eagles is linked to biomagnification of which chemical?Which two groups of substances are well known to biomagnify?A biomagnification factor above 1 means what?What is the opposite of biomagnification, where a pollutant falls in concentration up a food web?The word eutrophication comes from Greek eutrophos, which means what?Which two nutrients commonly cause eutrophication?Which nutrient usually limits plant growth in freshwater ecosystems?Which nutrient is the main limiting one in marine ecosystems?What happens when bacteria decompose dead algae?Eutrophication caused by human activity is called what?Water bodies with very low nutrient levels are termed what?Ozone depletion over the south pole in spring is commonly called what?The main manufactured chemicals that deplete the ozone layer are the:Which radiation does the ozone layer prevent from reaching Earth's surface?Which health problem is linked to higher UVB from ozone thinning?Who invented CFCs as refrigerants in the 1930s?The Antarctic ozone hole forms during which season there?Which cloud type boosts chlorine ozone destruction in polar winter?In which year did 43 nations sign the Montreal Protocol?The Vienna Convention for protecting the ozone layer was signed in which year?World Ozone Day is observed on which date?Which gas is colorless, odorless and toxic, a product of incomplete fuel combustion?Sulfur dioxide in air is produced mostly by burning what?PM2.5 particles are smaller than what diameter?Which acid, formed from sulfur dioxide, is a key cause of acid rain?Acid rain in Northern Europe in the 1970s caused damage such as:Which natural source is a main origin of particulate matter?Which gas gives acid rain through nitric acid formation?Raising a river's temperature reduces which key factor for fish?A 2017 Lancet Commission found global pollution kills about how many yearly?Algal blooms in a lake can shade out which plants?Which organisms can help reduce nitrogen pollution in coastal waters?Which organisms are the main source of harmful algae blooms?Natural eutrophication happens through gradual accumulation of what?Which household product ingredient contributed to eutrophication before the 1970s?CFCs found in the atmosphere come mostly from which source?By about which year is the ozone hole expected to reach pre-1980 levels?Antarctic ozone levels dropped to as low as what share of pre-1975 values?HFCs spare the ozone layer but are potent what?In which atmospheric layer does the ozone layer lie?Which atoms freed from CFCs by UV light catalyse ozone destruction?Ultrafine airborne particles are what size or smaller?Compared with natural particulate matter, human-made particles are usually:Natural water in the atmosphere is:Hydrochloric acid in acid rain comes from burning what?Acidic water and soil wash away which essential nutrients?Unlike bioaccumulation, biomagnification occurs across what?Why can heavy metals not be broken down in nature?