CBSE Class 12 Biology Environmental Issues MCQs Set 04

Practice MCQs for Class 12 Biology Chapter 16 Environmental Issues

Access targeted multiple-choice questions for Chapter 16 Environmental Issues designed to align with the latest CBSE academic syllabus for Class 12 Biology. These objective practice sets help students evaluate their conceptual understanding and improve exam readiness.

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Navigate directly to the 50 objective questions for Chapter 16 Environmental Issues using the digital viewer below. Each practice set includes verified answer keys, allowing students to instantly cross-check their work and identify areas requiring further revision.

Question : Lichens indicate SO2 pollution because they 
a) show association between algae and fungi
b) grow faster than others
c) are sensitive to SO2 
d) flourish in SO2 rich environment 

Answer: C

Question : Acid rains are produced by 
a) excess NO2 and SO2 from burning fossil fuels
b) excess production of NH3 by industry and coal gas
c) excess release of carbon monoxide by incomplete combustion
d) excess formation of CO2 by combustion and animal respiration 

Answer: A

 
Question : Green-house effect is warming due to 
a) infra-red rays reaching earth
b) moisture layer in atmosphere
c) increase in temperature due to increase in carbon dioxide concentration of atmosphere
d) ozone layer of atmosphere 

Answer: C

Question : Major aerosol pollutant in jet plane emission is 
a) sulphur dioxide
b) carbon monoxide
c) methane
d) chlorofluoro-carbons 

Answer: D

Question : Gas released during Bhopal tragedy was 
a) methyl isocyanate
b) potassium isothiocyanate
c) sodium isothiocyanate
d) ethyl isothiocyanate 

Answer: A

Question : Domestic waste constitutes 
a) non-biodegradable pollution
b) biodegradable pollution
c) effluents
d) air pollution 

Answer: B

Question : Which one is not a pollutant normally? 
a) Hydrocarbons
b) Carbon dioxide
c) Carbon monoxide
d) Sulphur dioxide 

Answer: B

Question : Most hazardous metal pollutant of automobile exhausts is 
a) mercury
b) cadmium
c) lead
d) copper 

Answer: C

Question : Ultraviolet radiations from sunlight cause a reaction which produces 
a) O3
b) SO2
c) CO
d) CH4 

Answer: A

Question : Drawback of DDT as pesticide is 
a) it becomes ineffective after some time
b) it is less effective than others
c) it is not easily/rapidly degraded in nature
d) its high cost 

Answer: C

Question : Highest DDT deposition shall occur in 
a) phytoplankton
b) sea gull/birds
c) crab
d) eel 

Answer: B

Question : Fish die in water bodies polluted by sewage due to 
a) pathogens
b) clogging of gills by silt
c) reduction in oxygen
d) fuel smell 

Answer: C

Question : Disease caused by eating fish found in water contaminated with industrial waste having mercury is 
a) Minamata disease
b) Blight’s disease
c) Hashimoto’s disease
d) Osteosclerosis 

Answer: A

Question : Sound becomes hazardous noise pollution at level
a) above 30 dB
b) above 80 dB
c) above 100 dB
d) above 120 dB 

Answer: B

Question : Atmosphere of big/metropolitan cities is polluted most by 
a) automobile exhausts
b) pesticide residue
c) household waste
d) radioactive fall-out 

Answer: A

Question : When huge amount of sewage is dumped into a river, its BOD will
a) increase
b) decrease
c) sharply decrease
d) remain unchanged 

Answer: A

Question : In Minamata Bay of Japan, the animals which remained free from Minamata disease, are 
a) pigs
b) rabbits
c) dogs
d) cats 

Answer: B

Question : The Taj Mahal is threatened due to the effect of 
a) oxygen
b) hydrogen
c) chlorine
d) sulphur dioxide 

Answer: D

Question : Sewage drained into water bodies kill fishes because 
a) excessive carbon dioxide is added to water
b) it gives off a bad smell
c) it removes the food eaten by fish
d) it increases competition with fishes for dissolved oxygen 

Answer: D

Question : The major contributor of green-house gases to the atmosphere is 
a) Russia
b) USA
c) Germany
d) Brazil 

Answer: B

Question : The worst environmental hazards were created by accidents in nuclear power plant and MIC gas tragedy respectively in
a) Russia in 1990 and Bhopal in 1986
b) Ukrain in 1988 and USA in 1984
c) Bhopal in 1984 and Russia in 1990
d) Ukrain in 1986 and Bhopal in 1984 

Answer: D

Question : If the forest cover is reduced to half, what is most likely to happen on a long term basis?
a) Tribals living in these areas will starve to death
b) Cattle in these and adjoining areas will die due to lack of fodder
c) Large areas will become deserts 
d) Crop breeding programmes will suffer due to a reduced availability of variety of germplasm 

Answer: C

Question : The most common indicator organism which represents polluted water is 
a) Escherichia coli
b) Salmonella typhi
c) Vibrio cholerae
d) Entamoeba histolytica 

Answer: A

Question : Phosphate pollution is mainly caused by
a) phosphate rock only [1997]
b) agricultural fertilizers only
c) sewage and phosphate rocks
d) sewage and agricultural fertilizers 

Answer: D

 

Question : The CO2 content by volume, in the atmospheric air is about 
a) 0.0314%
b) 0.34%
c) 3.34%
d) 4% 

Answer: A

Question : Formation of ozone hole is maximum over
a) India
b) Antarctica 
c) Europe
d) Africa 

Answer: B

Question : In coming years, skin related disorders will be more common due to 
a) air pollution
b) use of detergents
c) water pollution
d) depletion of ozone layer 

Answer: D

Question : Which one of the following organism is used as indicator of water quality ? 
a) Beggiatoa
b) Chlorella
c) Azospirillum
d) Escherichia 

Answer: D

Question : Which important green-house gas, other than methane, is being produced from the agricultural fields? 
a) Arsine
b) Sulphur dioxide
c) Ammonia
d) Nitrous oxide 

Answer: D

Question : The supersonic jets cause pollution by the thinning of 
a) CO2 layer
b) SO2 layer
c) O2 layer
d) O3 layer 

Answer: D

Question : Warm ocean surge of the peru current recurring every 5 to 8 year or so in the East Pacific of South America is widely known as 
a) Magnox
b) Gull stream
c) El Nino
d) Aye aye 

Answer: C

Question : Carbon monoxide is a pollutant because
a) it reacts with O2
b) it inhibits glycolysis
c) it reacts with haemoglobin
d) it makes nervous system inactive 

Answer: C

Question : If there was no CO2 in the earth’s atmosphere the temperature of earth’s surface would be
a) same as present 
b) less than the present
c) higher than the present
d) dependent on the amount of oxygen in the atmosphere 

Answer: B

 
Question : A sewage treatment process in which a portion of the decomposer bacteria present in the waste is recycled into the beginning of the process, is called 
a) cyclic treatment
b) primary treatment
c) activated sludge treatment
d) tertiary treatment 

Answer: C

Question : Which of the following is the use of lichens in case of pollution? 
a) Lichens are not related with pollution
b) They act as bioindicators of pollution
c) They treat the polluted water
d) They promote pollution  

Answer: B

Question : Which of the following is a secondary pollutant ? 
a) Aerosol
b) CO
c) PAN
d) CO2 

Answer: C

Question : Green-house effect refers to 
a) production of cereals
b) cooling of earth
c) trapping of UV rays
d) warming of earth 

Answer: D

Question : In 1984, Bhopal gas tragedy was caused due to the leakage of 
a) potassium isocyanate
b) sodium monoxide
c) sodium thiocyanate
d) methyl isocyanate 

Answer: D

Question : Which of the following is pollution related disorder ? 
a) Fluorosis
b) Leprosy
c) Pneumonicosis
d) Silicosis 

Answer: A

Question : Relative Biological Effectiveness [RBE] usually refers to the damages caused by 
a) low temperature
b) high temperature
c) radiation
d) pollution 

Answer: C

Question : What is the intensity of sound in normal conversation? 
a) 10-20 dB
b) 30-60 dB
c) 70-90 dB
d) 120-150 dB 

Answer: B

Question : What is BOD? 
a) The amount of O2 utilized by organisms in water
b) The amount of O2 utilized by microorganisms for decomposition
c) The total amount of O2 present in water
d) All of the above 

Answer: B

Question : Which of the following is absent in polluted water ? 
a) Hydrilla
b) Water hyacinth
c) Larva of stone fly
d) Blue-green algae 

Answer: C

Question : Fluoride pollution mainly affects 
a) teeth
b) kidney
c) brain
d) heart 

Answer: A

Question : If by radiation all nitrogenase enzymes are inactivated, then there will be no 
a) fixation of nitrogen in legumes
b) fixation of atmospheric nitrogen
c) conversion from nitrate to nitrite in legumes
d) conversion from ammonium to nitrate in soil 

Answer: A

Question : Lead concentration in blood is considered alarming if it is 
a) 20mg/100mL
b) 30mg/100mL
c) 4-6mg/100mL
d) 10mg/100mL 

Answer: B

Question : In 1984, the Bhopal gas tragedy took place because methyl isocyanate 
a) reacted with DDT
b) reacted with ammonia
c) reacted with CO2
d) reacted with water 

Answer: D

Question : Prolonged liberal irrigation of agricultural fields is likely to create the problem of 
a) acidity
b) aridity
c) metal toxicity 
d) salinity 

Answer: D

Question : Which of the following is not used for disinfection of drinking water? 
a) Phenyl
b) Chloramine
c) Chlorine
d) Ozone 

Answer: A

Question : Which one of the following pair is mismatched? 
a) Biomass burning — Release of CO2
b) Fossil fuel burning — Release of CO2
c) Nuclear power — Radioactive wastes
d) Solar energy — Green-house effect  

Answer: D

Question : Full form of B.O.D. is
a) Biological organism death
b) Biotic oxygen demand
c) Biochemical oxygen demand
d) Biological organisation day

Answer : C

 

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Download Chapter MCQs: Class 12 Biology Chapter 16 Environmental Issues

About Chapter 16 Environmental Issues MCQs for Class 12 Biology

Review structured objective questions for Class 12 Biology Chapter 16 Environmental Issues. Built according to official CBSE guidelines, these MCQ sets support daily revision and core concept reinforcement.

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FAQs

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