NEET Biology Environmental Issues MCQs Set 16

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Multiple Choice Questions

Question 1: 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
Show Answer & Explanation

Answer: (b) less than the present

Explanation:
1. Without CO2 there would be less greenhouse warming, so the earth would be cooler.

Teacher's Note:
1. The natural greenhouse effect keeps earth warm.
2. No CO2 means cooler earth.

Question 2: 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
Show Answer & Explanation

Answer: (c) activated sludge treatment

Explanation:
1. In the activated sludge process, part of the settled sludge with bacteria is recycled to the aeration tank.

Teacher's Note:
1. It is secondary treatment.
2. Recycled sludge is activated sludge.

Question 3: 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
Show Answer & Explanation

Answer: (b) They act as bioindicators of pollution

Explanation:
1. Lichens are sensitive to pollutants like SO2 and are used as bioindicators of pollution.

Teacher's Note:
1. They do not clean water.
2. Lichens are bioindicators.

Question 4: Which of the following is a secondary pollutant ?
(a) Aerosol
(b) CO
(c) PAN
(d) CO2
Show Answer & Explanation

Answer: (c) PAN

Explanation:
1. PAN (peroxyacyl nitrate) forms in air by reactions of other pollutants in sunlight, so it is a secondary pollutant.

Teacher's Note:
1. Primary pollutants are emitted directly.
2. PAN is secondary.

Question 5: Green-house effect refers to
(a) production of cereals
(b) cooling of earth
(c) trapping of UV rays
(d) warming of earth
Show Answer & Explanation

Answer: (d) warming of earth

Explanation:
1. Greenhouse effect is the warming of earth's surface and lower atmosphere by gases that trap heat.

Teacher's Note:
1. It is natural but enhanced by humans.
2. It warms the earth.

Question 6: In 1984, Bhopal gas tragedy was caused due to the leakage of
(a) potassium isocyanate
(b) sodium monoxide
(c) sodium thiocyanate
(d) methyl isocyanate
Show Answer & Explanation

Answer: (d) methyl isocyanate

Explanation:
1. Methyl isocyanate gas leaked from the Union Carbide plant at Bhopal in 1984.

Teacher's Note:
1. It was stored in tanks.
2. MIC leaked at Bhopal.

Question 7: Relative Biological Effectiveness [RBE] usually refers to the damages caused by
(a) low temperature
(b) high temperature
(c) radiation
(d) pollution
Show Answer & Explanation

Answer: (c) radiation

Explanation:
1. Relative biological effectiveness compares the biological damage caused by different kinds of radiation.

Teacher's Note:
1. It is used in radiation protection.
2. RBE refers to radiation.

Question 8: Fluoride pollution mainly affects
(a) teeth
(b) kidney
(c) brain
(d) heart
Show Answer & Explanation

Answer: (a) teeth

Explanation:
1. Excess fluoride in water causes fluorosis, mainly affecting teeth and bones.

Teacher's Note:
1. Teeth become mottled.
2. Fluoride affects teeth.

Question 9: 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
Show Answer & Explanation

Answer: (d) reacted with water

Explanation:
1. Water entered a tank of methyl isocyanate at Bhopal and caused a violent reaction that released the gas.

Teacher's Note:
1. It happened on the night of 2-3 December.
2. MIC reacted with water.

Question 10: Prolonged liberal irrigation of agricultural fields is likely to create the problem of
(a) acidity
(b) aridity
(c) metal toxicity
(d) salinity
Show Answer & Explanation

Answer: (d) salinity

Explanation:
1. Long irrigation without drainage brings salts to the surface and makes soil saline.

Teacher's Note:
1. Evaporation leaves salts behind.
2. Over-irrigation causes salinity.

Question 11: 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
Show Answer & Explanation

Answer: (d) Solar energy — Green-house effect

Explanation:
1. Solar energy is clean and does not cause greenhouse effect, so this pair is mismatched.

Teacher's Note:
1. The other pairs are right.
2. Solar energy gives no greenhouse gases.

Question 12: Photochemical smog pollution does not contain
(a) ozone
(b) nitrogen dioxide
(c) carbon dioxide
(d) PAN [Peroxy Acyl Nitrate]
Show Answer & Explanation

Answer: (c) carbon dioxide

Explanation:
1. Photochemical smog has ozone, NO2 and PAN formed in sunlight. CO2 is not a characteristic component.

Teacher's Note:
1. It forms in traffic areas.
2. CO2 is not in smog list.

Question 13: Montreal Protocol which calls for appropriate action to protect the ozone layer from human activities was passed in the year
(a) 1986
(b) 1987
(c) 1988
(d) 1985
Show Answer & Explanation

Answer: (b) 1987

Explanation:
1. The Montreal Protocol to protect the ozone layer was adopted in 1987.

Teacher's Note:
1. It phases out CFCs.
2. Montreal Protocol is of 1987.

Question 14: In a coal fired power plant electrostatic precipitators are installed to control emission of
(a) SO2
(b) NOX
(c) SPM
(d) CO
Show Answer & Explanation

Answer: (c) SPM

Explanation:
1. Electrostatic precipitators remove suspended particulate matter from the exhaust of power plants.

Teacher's Note:
1. They charge the particles.
2. Precipitators remove SPM.

Question 15: Which one of the following is not a bioindicator of water pollution ?
(a) Sludge worms
(b) Blood worms
(c) Stone flies
(d) Sewage fungus
Show Answer & Explanation

Answer: (c) Stone flies

Explanation:
1. Sludge worms, blood worms and sewage fungus live in polluted water. Stone fly nymphs need clean water.

Teacher's Note:
1. Different animals indicate different pollution.
2. Stone flies are clean-water species.

Question 16: A lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this (1) Lots of urea and phosphate fertilizer were used in the crops in the vicinity. (2) The area was sprayed with DDT by an aircraft. (3) The lake water turned green and stinky. (4) Phytoplankton populations in the lake declined initially thereby greatly reducing photosynthesis. Which two of the above were the main causes of fish mortality in the lake?
(a) 2, 3
(b) 3, 4
(c) 1, 3
(d) 1, 2.
Show Answer & Explanation

Answer: (c) 1, 3

Explanation:
1. Fertilizer run-off caused algal bloom and the green stinking water; fish died from oxygen depletion. So 1 and 3 are the main causes.

Teacher's Note:
1. Phytoplankton increase in bloom.
2. Fertilizer and bloom killed the fish.

Question 17: World Summit on Sustainable Development was held in
(a) Brazil
(b) Sweden
(c) Argentina
(d) South Africa
Show Answer & Explanation

Answer: (d) South Africa

Explanation:
1. The World Summit on Sustainable Development was held in Johannesburg, South Africa, in 2002.

Teacher's Note:
1. The Earth Summit was at Rio.
2. The summit was in South Africa.

Question 18: According to Central Pollution Control Board (CPCB), which paniculate size in diameter (in micrometers) of the air pollutants is responsible for greatest harm to human health?
(a) 2.5 or less
(b) 1.5 or less
(c) 1.0 or less
(d) 5.2 or 2.5
Show Answer & Explanation

Answer: (a) 2.5 or less

Explanation:
1. Particles of 2.5 micrometres or less reach deep into the lungs, so they harm health the most.

Teacher's Note:
1. They are called PM 2.5.
2. PM 2.5 is most harmful.

Question 19: Which one of the following is the correct percentage of the two (out of the total of 4) greenhouse gases that contribute to the total global warming?
(a) CFCs 14%, CH4 20%
(b) CO2 40%, CFCs 30%
(c) N2O 6%, CO2 86%
(d) CH4 20%, N2O 18%
Show Answer & Explanation

Answer: (a) CFCs 14%, CH4 20%

Explanation:
1. Contributions to global warming are about CO2 60, CH4 20, CFCs 14 and N2O 6 percent, so CFCs 14 and CH4 20 are right.

Teacher's Note:
1. CO2 contributes the most.
2. CFCs 14 and CH4 20 percent.

Question 20: Steps taken by the Government of India to control air pollution include:
(a) Permission to use only pure diesel with a maximum of 500 ppm sulphur as fuel for vehicles.
(b) use of non-polluting Compressed Natural Gas (CNG) only as fuel by all buses and trucks.
(c) compulsory mixing of 20% ethyl alcohol with petrol & 20% biodiesel with diesel.
(d) compulsory PUC (Pollution Under Control) certification of petrol driven vehicles which tests for carbon monoxide and hydrocarbons.
Show Answer & Explanation

Answer: (d) compulsory PUC (Pollution Under Control) certification of petrol driven vehicles which tests for carbon monoxide and hydrocarbons.

Explanation:
1. India made PUC certification compulsory for petrol vehicles, testing CO and hydrocarbons.

Teacher's Note:
1. Other options overstate the rules.
2. PUC checks vehicle exhaust.

Question 21: Biochemical Oxygen Demand (BOD) in a river water:
(a) gives a measure of salmonella in the water.
(b) increases when sewage gets mixed with river water.
(c) remains unchanged when algal bloom occurs.
(d) has no relationship with concentration of oxygen in the water.
Show Answer & Explanation

Answer: (b) increases when sewage gets mixed with river water.

Explanation:
1. Sewage adds organic matter which microbes decompose using oxygen, so BOD increases.

Teacher's Note:
1. BOD is linked to dissolved oxygen.
2. Sewage raises BOD.

Question 22: DDT residues are rapidly passed through food chain causing bio-magnification because DDT is
(a) non-toxic to aquatic animals
(b) water soluble
(c) lipo soluble
(d) moderately toxic
Show Answer & Explanation

Answer: (c) lipo soluble

Explanation:
1. DDT dissolves in fats (lipo soluble), is stored in body tissues and passes up food chains, causing biomagnification.

Teacher's Note:
1. It is not water soluble.
2. Fat solubility causes biomagnification.

Question 23: Montreal Protocol aims at
(a) Control of water pollution
(b) Control of CO2 emission
(c) Reduction of ozone depleting substances
(d) Biodiversity conservation
Show Answer & Explanation

Answer: (c) Reduction of ozone depleting substances

Explanation:
1. The Montreal Protocol aims to reduce substances that deplete the ozone layer.

Teacher's Note:
1. Kyoto concerns greenhouse gases.
2. It protects the ozone layer.

Question 24: Select the correct statement from the following
(a) Biogas is produced by the activity of aerobic bacteria on animal waste
(b) Methanobacterium is an aerobic bacterium found in rumen of cattle
(c) Biogas, commonly called gobar gas, is pure methane
(d) Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria.
Show Answer & Explanation

Answer: (b) Methanobacterium is an aerobic bacterium found in rumen of cattle

Explanation:
1. Methanobacterium is an anaerobic methanogen found in the rumen of cattle and in biogas plants. Other statements are wrong as biogas is a mixture and anaerobic.

Teacher's Note:
1. Gobar gas contains methane, CO2 and H2S.
2. Methanobacterium is in the rumen.

Question 25: dB is a standard abbreviation used for the quantitative expression of
(a) the density of bacteria in a medium
(b) a particular pollutant
(c) the dominant Bacillus in a culture
(d) a certain pesticide
Show Answer & Explanation

Answer: (b) a particular pollutant

Explanation:
1. The decibel (dB) is the unit of sound level, so it expresses a pollutant (noise).

Teacher's Note:
1. Noise is a pollutant.
2. dB measures noise.

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