CBSE 12th Standard Biology Subject Environmental Issues Ncert Exemplar MCQ Questions With Solution 2021
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CBSE 12th Standard Biology Subject Environmental Issues Ncert Exemplar MCQ Questions With Solution 2021
12th Standard CBSE
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Reg.No. :
Biology
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More than 70% of world's fresh water is contained in
(a)polar ice
(b)glaciers and mountains
(c)Antarctica
(d)Greenland
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Which one of the following statements pertaining to pollutants is correct?
(a)DDT is a non-biodegradable pollutant
(b)excess fluoride in drinking water causes osteoporosis.
(c)excess cadmium in drinking water causes black foot disease.
(d)methyl mercury in water may cause 'Itai Itai' disease.
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In a coal fired power plant electrostatic precipitators are installed to control emission of
(a)NOX
(b)SPM
(c)CO
(d)SO2
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Ozone is spread in the swimming pool because
(a)it acts as disinfectant
(b)it absorbs UV radiations
(c)ozone is easily available from O2
(d)all of the above
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Which one of the following is the correct percentage of the two green house gases that contribute to the total global warming?
(a)N2O 6%, CO2 86%
(b)methane 20%, N2O 18%
(c)CFCs 14%, methane 20%
(d)CO2 40%, CFCs 30%
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A lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this.
(a) lots of urea and phosphate fertilizers were used in the crops in the vicinity
(b) the area was sprayed with DDT by an aircraft
(c) the lake water turned green and stinky
(d) phytoplankton populations in the lake declined initially thereby greatly reducing photosynthesis
Which two of the above were main reasons of fish mortality in the lake?(a)A, C
(b)A, B
(c)B, C
(d)C, D
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Photochemical smog is caused by a light mediated reaction between
(a)NO2 and unsaturated hydrocarbons
(b)NO2 and O3
(c)SO2 and unburnt hydrocarbons
(d)SO2 and O3
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Catalytic converters are fitted into automobiles to reduce emission of harmful gases. Catalytic converters change unburnt hydrocarbons into:
(a)carbon dioxide and water
(b)carbon monoxide
(c)methane
(d)carbon dioxide and methene
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Nuisance growth of aquatic plants and bloom-forming algae in natural waters is generally due to high concentration of:
(a)carbon
(b)sulphur
(c)calcium
(d)phosphorus
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Algal blooms impart a distinct colour to water due to:
(a)their pigments
(b)excretion of coloured substances
(c)formation of coloured chemicals in water facilitated by physiological degradation of algae.
(d)absorption of light by algal cell wall.
Multiple Choice Questions
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CBSE 12th Standard Biology Subject Environmental Issues Ncert Exemplar MCQ Questions With Solution 2021 Answer Keys
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(a)
polar ice
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(a)
DDT is a non-biodegradable pollutant
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(b)
SPM
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(a)
it acts as disinfectant
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(c)
CFCs 14%, methane 20%
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(b)
A, B
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(a)
NO2 and unsaturated hydrocarbons
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(a)
carbon dioxide and water
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(d)
phosphorus
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(a)
their pigments
Multiple Choice Questions
