Students of class 12 Biology should refer to MCQ Questions Class 12 Biology Environmental Issues with answers provided here which is an important chapter in Class 12 Biology NCERT textbook. These MCQ for Class 12 Biology with Answers have been prepared based on the latest CBSE and NCERT syllabus and examination guidelines for Class 12 Biology. The following MCQs can help you to practice and get better marks in the upcoming class 12 Biology examination

Chapter 16 Environmental Issues MCQ with Answers Class 12 Biology

MCQ Questions Class 12 Biology Environmental Issues provided below have been prepared by expert teachers of grade 12. These objective questions with solutions are expected to come in the upcoming Standard 12 examinations. Learn the below provided MCQ questions to get better marks in examinations.

Question. Biochemical oxygen demand (BOD) in a river water
(a) has no relationship with concentration of oxygen in the water
(b) gives a measure of Salmonella in the water
(c) increases when sewage gets mixed with river water
(d) remains unchanged when algal bloom occurs.

Question. Motor vehicles equipped with catalytic converter are advised to use unleaded petrol because
(a) lead causes inactivation of catalyst.
(b) lead reduces the emission of poisonous gases.
(c) lead is a heavy metal.
(d) lead decreases the efficiency of vehicle.

Question. Montreal Protocol aims at
(a) biodiversity conservation
(b) control of water pollution
(c) control of CO₂ emission
(d) reduction of ozone depleting substances

Question. Nuclear power stations even with adequate radiation safety measures generate
(a) thermal pollution of water bodies.
(b) thermal pollution of soil.
(c) noise polllution.
(d) all of the above

Question. Eutrophication is often seen in
(a) deserts
(b) fresh water lakes
(c) ocean
(d) mountains

Question. “Good ozone” is found in the
(a) mesosphere
(b) troposphere
(c) stratosphere
(d) ionosphere

Question. In an area where DDT had been used extensively population of birds declined significantly because
(a) birds stopped laying eggs
(b) earthworms in the area got eradicated
(c) cobras were feeding exclusively on birds
(d) many of the birds laid eggs, did not hatch

Question. Compressed Natural Gas (CNG) is
(a) propane
(b) methane
(c) ethane
(d) butane

Question. Which one of the following impurities is easiest to remove from wastewater?
(a) Bacteria
(b) Colloids
(c) Dissolved solids
(d) Suspended solids

Question. World’s most problematic aquatic weed is
(a) Azolla
(b) Wolffia
(c) Eichhornia
(d) Trapa

Question. Which of the following exhibits biomagnification?
(a) SO₂
(b) Mercury
(c) DDT
(d) Both (b) and (c)

Question. Match the items given in Column I with those in Column II and select the correct option given below:
        Column I           Column II
A. Eutrophication        (i) UV-B radiation
B. Sanitary landfills     (ii) Deforestation
C. Snow blindness      (iii) Nutrient enrichment
D. Jhum cultivation     (iv) Waste diposal
(a) A-(iii), B-(iv), C-(i), D-(ii)
(b) A-(i), B-(iii), C-(iv), D-(ii)
(c) A-(ii), B-(i), C-(iii), D-(iv)
(d) A-(i), B-(ii), C-(iv), D-(iii)

Question. Natural ageing of lake by biological enrichment of its water is called
(a) biomagnification
(b) eutrophication
(c) biodegradation
(d) water logging

Question. The expanded form of DDT is
(a) dichloro diphenyl trichloroethane
(b) dichloro diethyl trichloroethane
(c) dichloro dipyrydyl trichloroethane
(d) dichloro diphenyl tetrachloroacetate

Question. Choose the incorrect statement.
(a) The Montreal protocol is associated with the control of emission of ozone depleting substances
(b) Methane and carbon dioxide are green house gases
(c) Dobson units are used to measure oxygen content of air
(d) Use of incinerators is crucial to disposal of hospital wastes

Question. The green scum seen in the fresh water bodies is:
(a) blue green algae
(b) red algae
(c) green algae
(d) both (a) and (c)

Question. The presence of ozone in the atmosphere of earth 
(a) is advantageous since it supplies O2 for people travelling in jets.
(b) helps in checking the penetration of ultraviolet rays to earth.
(c) hinder higher rate of photosynthesis.
(d) has been responsible for increasing the average global temperature in recent years.

Question. The major source of noise pollution world wide is due to
(a) office equipment
(b) transport system
(c) sugar, textile and paper industries
(d) oil refineries and thermal power plants.

Question. Mark the correct statement.
(a) The ozone of stratosphere is good ozone.
(b) Troposphere, on top of stratosphere, is away from earth surface.
(c) The thickness of ozone is measured in dB.
(d) The wavelength of UV- B is more than that of UV- A.

Question. Match the following and choose the correct option.
Column I Column II
A. Environment Protection Act (i) 1974
B. Air Prevention & Control of Pollution Act (ii) 1987
C. Water Act (iii) 1986
D. Amendment of Air Act to include noise (iv) 1981
as an air pollutant
The correct matches is
(a) A-(iii), B-(iv), C-(i), D-(ii)
(b) A-(i), B-(iii), C-(ii), D-(iv)
(c) A-(iv), B-(i), C-(ii), D-(iii)
(d) A-(iii), B-(iv), C-(ii), D-(i)

Question. Increased rate of skin cancer and mutation might be because of
(a) increase in CO₂ concentration
(b) increase in CO concentration
(c) ozone layer depletion
(d) acid rain

Question. 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 methane

Question. Nuisance growth of aquatic plants and bloom-forming algae in natural waters is generally due to high concentrations of
(a) carbon
(b) sulphur
(c) calcium
(d) phosphorus

Question. 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.

Question. Match the items in column I and column II and choose the correct option.
         Column I                                  Column II
A. UV                                         (i) Biomagnification
B. Biodegradable Organic matter  (ii) Eutrophication
C. DDT                                      (iii) Snow blindness
D. Phosphates                            (iv) BOD
The correct match is:
(a) A-(ii), B-(i), C-(iv), D-(iii)
(b) A-(iii), B-(ii), C-(iv), D-(i)
(c) A-(iii), B-(iv), C-(i), D-(ii)
(d) A-(iii), B-(i), C-(iv), D-(ii)

Question. Non-biodegradable pollutants are created by
(a) nature
(b) excessive use of resources
(c) humans
(d) natural disasters

Question. In the textbook you came across “Three Mile Island and Chernobyl disasters associated with accidental leakage of radioactive wastes.” In India we had Bhopal gas tragedy. It is associated with which of the following?
(a) CO₂
(b) Methyl Isocyanate
(c) CFC
(d) Methyl Cyanate

Question. Which one of the following is a most efficient device to eliminate particulate matters from the industrial emissions ?
(a) Cyclonic separators
(b) Trajectory separators
(c) Incineration
(d) Electrostatic precipitator

Question. Euro II norms stipulate that sulphur be controlled at _______ ppm in diesel and _______ ppm in petrol.
(a) 350; 150
(b) 150; 350
(c) 350; 250
(d) 150; 250

Question. Which of the following material takes the longest time for biodegradation?
(a) Cotton
(b) Paper
(c) Bone
(d) Jute

Question. Which one of the following statement pertaining to pollutants is correct?
(a) DDT is a non-biodegradable pollutant.
(b) Excess fluoride in drinking water causes osteoporosis, hardening of bones, stiff joints.
(c) Excess cadmium in drinking water causes black foot disease.
(d) Methylmercury in water may cause “Itai Itai” disease.

Question. Why is it necessary to remove sulphur from petroleum products?
(a) To reduce the emission of sulphur dioxide in exhaust fumes
(b) To increase efficiency of automobiles engines
(c) To use sulphur removed from petroleum for commercial purposes
(d) To increase the life span of engine silencers

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

Question. All automobiles and fuel -petrol and diesel were to have met the Euro III emission specifications in some cities from 1 April 2005 and have to meet the Euro-IV norms by
(a) 1 April 2008
(b) 1 April 2009
(c) 1 April 2010
(d) 1 April 2012

Question. Presence of large amount of nutrients in water also cause excess growth of planktonic (free-floating) algae, called ___________.
(a) biomagnification
(b) eutrophication
(c) algal bloom
(d) biofortification

Question. The two gases making highest relative contribution to greenhouse gases are
(a) CO₂ and CH₄
(b) CH₄ and N₂O
(c) CFCs and N₂O
(d) CO₂ and N₂O

Question. DDT causes egg shell thinning in birds because it inhibits
(a) calmodulin
(b) calcium ATPase
(c) magnesium ATPase
(d) carbonic anhydrase

Question. Without Green house effect the average temperature of earth surface would have been
(a) 18 °C
(b) 8°C
(c) – 8°C
(d) –18°C

Question. Slash and burn agriculture, which is commonly known as Jhum cultivation in the north-eastern states of India, leads to
(a) deforestation
(b) reforestation
(c) desertification
(d) water-logging

Question. Pollution in big cities can be controlled to a large extent by
(i) improving traffic condition and road.
(ii) road side plantation
(iii) proper disposal of garbage and domestic as well as municipal wastes.
(iv) cannot be controlled
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) all of these

Question. Global warming can be controlled by
(a) reducing reforestation, increasing the use of fossil fuel.
(b) increasing deforestation, slowing down the growth of human population.
(c) increasing deforestation, reducing efficiency of energy usage.
(d) reducing deforestation, cutting down use of fossil fuel

Question. Which of the following statements about eutrophication are ?
(i) It can be a naturally occurring process.
(ii) It is commonly found in standing rather than running water.
(iii) It can lead to oxygen depletion.
(iv) It is commonly associated with high levels of phosphates and nitrates.
(a) (iii) and (iv)
(b) (i), (ii) and (iii)
(c) (ii), (iii) and (iv)
(d) all of these

Question. ‘EcoSan’ toilets, being used in Kerala and Sri Lanka are hygienic and cost effective solution to human waste disposal. Mark the correct statement regarding EcoSan.
(a) Recycled human waste from this can be used as a natural fertilizer.
(b) They are called composting toilets.
(c) They do not depend on water for the disposal of excreta.
(d) All of the above

Question. The scrubber is used mainly to remove which of the following gas/es from the exhaust after spraying water/lime ?
(a) CO2
(b) SO2
(c) O2 and N2
(d) CO and CO2

Question. CNG is better than petrol/ diesel, since
(a) CNG burns more efficiently.
(b) CNG burns completely.
(c) CNG cannot be adulterated.
(d) All of the above

Question. Two lakes, A and B are identical in all aspects except that lake A has higher temperature. Which of the following is true ?
(a) A has higher rate of oxygen dissolution.
(b) B has higher rate of oxygen dissolution.
(c) Oxygen dissolution of both is the same.
(d) Both the lakes have same BOD.

Question. Today the concentration of green house gases is very high because of
(a) use of refrigerator.
(b) increased combustion of oils and coal.
(b) deforestation.
(d) all of the above

Question. Which of these is not an advantage of CNG over diesel?
(a) Burns more efficiently.
(b) It is cheap.
(c) Cannot be siphoned off by thieves.
(d) Easy to lay down pipelines for delivery.

Question. The effect of todays radioactive fall out will be harmful to children of future generation because
(a) infants are more susceptible to radiations.
(b) susceptibility to radiation increase with age.
(c) mutated genes are frequently recessive.
(d) contamination of milk supply is not cumulative

Question. Among the following which one causes maximum indoor chemical pollution?
(a) Burning coal
(b) Burning cooking gas
(c) Burning mosquito coil
(d) Room spray

Question. 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.

Question. In B.O.D. test oxygen plays an important role to
(a) destroy inorganic matter
(b) destroy pollution
(c) destroy waste organic matter
(d) none of these

Question. In the 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

We hope the above multiple choice questions for Class 12 Biology for Chapter 16 Environmental Issues provided above with answers based on the latest syllabus and examination guidelines issued by CBSE, NCERT and KVS are really useful for you. Environmental Issues is an important chapter in Class 12 as it provides very strong understanding about this topic. Students should go through the answers provided for the MCQs after they have themselves solved the questions. All MCQs have been provided with four options for the students to solve. These questions are really useful for benefit of class 12 students. Please go through these and let us know if you have any feedback in the comments section.