Top 100+ Environmental Issues - Biology Questions and Answers For NEET 2024 Exam Preparation

Q1. Today the concentration of greenhouse gases is very high because of

1. Increased combustion of oils and coal
2. Use of refrigerator
3. Deforestation
4. All of the above

Answer: (d)

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Q2. Global warming can be controlled by

1. Reducing reforestation, increasing the use of fossil fuel.
2. Reducing deforestation, cutting down the use of fossil fuel.
3. Increasing deforestation, slowing down the growth of human population.
4. Increasing deforestation, reducing the efficiency of energy usage.

Answer: (b)

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Q3. Assertion: Water hyacinth is an aquatic weed.

Reason: They grow abundantly in eutrophic water bodies.

1. If both the assertion and reason are true but the reason is not a correct explanation of the assertion.
2. If both the assertion and the reason are true and the reason is a correct explanation of the assertion.
3. If the assertion is true but the reason is false.
4. If both the assertion and reason are false.

Answer: (b)

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Q4. Which of the following figures shows correct relative contribution of greenhouse gases to global warming?

Answer: (a)

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Q5. EcoSan' toilets have been made effective in many areas of:

1. Sri Lanka
2. Kerala
3. Both (a) and (b)
4. None of these

Answer: (c)

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Q6. The solid wastes can best be managed

1. by municipality agencies
2. by open burning dumps
3. by sanitary landfills
4. All of the above

Answer: (d)

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Q7. Montreal Protocol which calls for appropriate action to protect the ozone layer from human activities was passed in the year

1. 1987
2. 1986
3. 1988
4. 1985

Answer: (a)

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Q8. Jhum cultivation refers to

1. cultivation of medicinal plants
2. cultivation of neem tress
3. tribal method of shifting cultivation
4. cultivation of timber plants

Answer: (c)

In tribal North-Eastern states of India, farmers perform Jhum cultivation in which trees of the forest are cut down and burned. The ash produced is used as a fertiliser and the land is then used for farming or cattle grazing.

After cultivation, the area is left for several years to allow its recovery and repeat this process in another area. Thus, this shifting cultivation method also contributes in deforestation.

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Q9. Which of the following statement (s) is/are not correct regarding biomagnification?

1. Accumulation of zinc can cause thinning of eggshell in birds
2. Heavy metals and persistent pesticides pass into food chain and increases in amount per unit weight of organisms with the rise in trophic level due to their accumulation in fat
3. DDT accumulation is a major cause of killing of fish-eating birds
4. Biomagnification occurs in all aquatic food chain

Answer: (a)

The incorrect Statement can be corrected as

Higher amounts of the pesticide (DDT) disturbs calcium metabolism in birds and causes thinning of eggshells. Rest of the statements are correct.

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Q10. The Taj Mahal is threatened due to the effect of

1. hydrogen
2. oxygen
3. chlorine
4. sulphur dioxide

Answer: (d)

The Taj Mahal is built with white marble and is threatened by environmental pollution, especially due to sulphur dioxide. Sulphur dioxide is produced during combustion of fossil fuels, refining of petroleum and smelting of sulphur containing ores.

Threat to Taj Mahal from Mathura refinery is due to pollutant gases composing $SO_2, H_2S$ and nitrogen oxides. They would convert $CaCO_3$ (marble) into calcium sulphate and calcium nitrate.

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Q11. Biochemical Oxygen Demand (BOD) may not be a good index for pollution in water bodies receiving effluents from

1. dairy industry
2. domestic sewage
3. petroleum industry
4. sugar industry

Answer: (c)

Biochemical Oxygen Demand (BOD) is not a good index for checking the pollution levels of waterbodies receiving effluents from petroleum industry. This is because petroleum industries release non-biodegradable waste, which cannot be degraded by microbes.

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Q12. Hyacinth is termed as the terror of Bengal, how it causes death of fishes?

1. Drains oxygen from the water that causes oxygen deficiency
2. Covers the surface of the water that inhibits sunlight to pass through
3. Absorbs nutrients from the water that causes malnutrition
4. Releases carbon dioxide in a huge amount which is lethal to fishes

Answer: (a)

Water hyacinth (Eichhornia) causes death of fishes as it reduces the $O_2$ level in water.

It is termed as the terror of Bengal because it drains dissolved oxygen of the water, i.e. increases BOD (Biochemical Oxygen Demand). It grows abundantly in eutrophic water body and imbalances water ecosystem, leading to the death of fishes.

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Q13. Which of the following statements is not correct regarding jhum cultivation?

1. It helps in increasing crop yield to a considerable extent.
2. It is also called as shifting cultivation and has resulted in deforestation
3. A time gap of several years is required for the recovery of the land after cultivation.
4. It involves cutting down of trees of the forest, burning of the plant remains and then using the land for farming.

Answer: (a)

In Jhum cultivation crops are cultivated for 2-3 years without manuring. It results in nutrient depletion, reduced moisture retention of soil and increased soil erosion.

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Q14. The second commitment period for Kyoto Protocol was decided at

1. Bali
2. Durban
3. Doha
4. Cancun

Answer: (c)

International conference held in Kyoto, Japan obtained commitments from different countries for reducing overall greenhouse gas emissions at a level 5% below than that in 1990 by 2008-2012. In Doha, Qatar on 8th December 2012, the "Doha amendment to the Kyoto Protocol" was adopted. The second commitment period is from 1st January 2013 to 31st December 2020.

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Q15. Which one of the following pairs is mismatched?

1. Nuclear power – radioactive wastes
2. Fossil fuel burning – release of $CO_2$
3. Solar energy – greenhouse effect
4. Biomass burning – release of $CO_2$

Answer: (c)

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Q16. A dental disease characterized by mottling of teeth is due to the presence of certain chemical element in drinking water. Which of the following is that element?

1. Boron
2. Fluorine
3. Mercury
4. Chlorine

Answer: (b)

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Q17. Identify A, B, C and D in the diagram.

1. A: Clean air, B: Water line spray, C: Particulate matter, D: Dirty air
2. A: Dirty air, B: Water line spray, C: Clean air, D: Particulate matter
3. A: Water line spray, B: Particulate matter, C: Clean air, D: Dirty air
4. A: Particulate matter, B: Dirty air, C: Clean air, D: Water line spray

Answer: (a)

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Q18. Catalytic converters are fitted into automobiles to reduce the emission of harmful gases. Catalytic converters change unburnt hydrocarbons into

1. Carbon monoxide
2. Carbon dioxide and water
3. Methane
4. Carbon dioxide and methane.

Answer: (b)

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Q19. Which of the following is not one of the prime health risks associated with greater UV radiation due to depletion of stratospheric ozone?

1. Increased skin cancer
2. Increased liver cancer
3. Damage to eyes
4. Reduced immune system

Answer: (b)

UV-radiations are harmful for living beings. These radiations cause harm to the DNA, RNA and protein. It also causes ageing of skin, damage to skin cells and various types of skin cancers.

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Q20. The effect of todays radioactive fallout will be harmful to children of future generation because

1. susceptibility to radiation increase with age.
2. infants are more susceptible to radiations.
3. mutated genes are frequently recessive.
4. contamination of milk supply is not cumulative.

Answer: (c)

The effect of today's radioactive fallout will be harmful to children of future generation because its affects the DNA structure.

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Q21. Sewage drained into water bodies kill fishes because

1. it gives off a bad smell
2. excessive carbon dioxide is added to water
3. it removes the food eaten by fish
4. it increases competition with fishes for dissolved oxygen

Answer: (d)

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Q22. Deforestation will decrease

1. land slides
2. soil erosion
3. soil fertility
4. rainfall

Answer: (d)

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Q23. Which of the following materials takes the longest time for biodegradation?

1. Paper
2. Cotton
3. Bone
4. Jute

Answer: (c)

Out of the given options, bone takes the longest time for biodegradation as it is made up of protein fraction, mineral fraction and organic compounds.

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Q24. The Taj Mahal is threatened due to the effect of

1. hydrogen
2. oxygen
3. chlorine
4. sulphur-dioxide.

Answer: (d)

The Taj Mahal is built with white marble and is threatened by environmental pollution, especially due to sulphur dioxide. Sulphur dioxide is produced during combustion of fossil fuels, refining of petroleum and smelting of sulphur-containing ores.

Threat to Taj Mahal from Mathura refinery is due to pollutant gases composing $SO_2, H_2 S$ and nitrogen oxides. They would convert CaC$O_3$ (marble) into calcium sulphate and calcium nitrate.

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Q25. Which one of the following is a wrong statement?

1. Ozone in upper part of atmosphere is harmful to animals.
2. Most of the forests have been lost in tropical areas.
3. Greenhouse effect is a natural phenomenon.
4. Eutrophication is a natural phenomenon in freshwater bodies

Answer: (a)

Ozone present in upper atmosphere forms a distinct layer that is known as ozone layer. Ozone layer is necessary for the survival of life on earth as it blocks harmful UV rays of sun from reaching earth's surface.

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Q26. “Good ozone “ is found in the

1. troposphere
2. mesosphere
3. stratosphere
4. ionosphere

Answer: (c)

Good ozone occurs naturally in the earth ’s upper atmosphere 10 to 30 miles above earth ’s surface(stratosphere) where it forms a protective layer that shield us from the sun ’s harmful ultraviolet rays.

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Q27. What is the intensity of sound in normal conversation?

1. 30-60 dB
2. 10-20 dB
3. 70-90 dB
4. 120-150 dB

Answer: (a)

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Q28. In stratosphere, which of the following elements acts as a catalyst in degradation of ozone and release of molecular oxygen?

1. Cl
2. Carbon
3. Fe
4. Oxygen

Answer: (a)

UV rays act on chlorofluorocarbons (CFCs) releasing active chlorine (Cl, ClO) which further reacts with ozone in sequential manner thereby converting it into oxygen.

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Q29. Assertion: Eutrophication shows increase in productivity in water.

Reason: With increasing eutrophication, the diversity of the phytoplankton increases.

1. If both Assertion and Reason are true but the Reason is not the correct explanation of the Assertion.
2. If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
3. If Assertion is true but Reason is false.
4. If both Assertion and Reason are false.

Answer: (a)

Eutrophication is a natural process which literally means well nourished or enriched. It is a natural state in many lakes and ponds which have a rich supply of nutrients. Eutrophication become excessive, however when abnormally high amount of nutrient from sewage, fertilizers, animal wastage and detergent, enter streams and lakes causing excessive growth or blooms of microorganisms.

With increasing eutrophication, the diversity of the phytoplankton community of a lake increases and the lake finally becomes dominated by blue-green algae.

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Q30. Which of the following are most suitable indicators of $SO_2$ pollution in the environment?

1. Fungi
2. Algae
3. Lichens
4. Conifers

Answer: (c)

Lichens are very sensitive to $SO_2$ pollution. They are completely destroyed at places where there is $SO_2$ pollution in atmosphere. Therefore, they act as very good indicators of $SO_2$ pollution.

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Q31. The material generally used for sound proofing of rooms like a recording studio and auditorium etc., is

1. coir
2. cotton
3. wood
4. styrofoam

Answer: (d)

The material generally used for rooms sound proofing like in recording studio, cinema hall, auditorium which absorb sound and facilitate in proofing is styro foam. Earplugs is the device used by working person of commercial and industrial zone, which are made up of very fine glass wood or cotton wood impregnated with wax while earmuffs contain fluid seals or plastic foam for absorbing sound.

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Q32. Which of the statements regarding the sources of air pollution is correct?

1. Decomposition of garbage does not result in the release of unwanted gases into the atmosphere
2. Smoke from forest fires, volcanic eruptions do not cause air pollution
3. Burning of fossil fuels in automobiles and industries releases particulate are noise pollutants
4. Use of leaded petrol in automobiles emit various pollutants

Answer: (d)

This statement is correct. Rest of the statements are incorrect and can be corrected as

• Smoke from forest fires, volcanic eruptions cause air pollution.
• Decomposition of garbage results in the release of unwanted gases into the atmosphere.
• Burning of fossil fuels and industries releases particulate are air pollutants.

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Q33. Assertion: Methane, component of greenhouse gases, contributing to global warming is about 20 percent.

Reason: Introduction of multi-point fuel injection engines in automobiles has decreased methane content in the exhausts.

1. If both Assertion and Reason are true but the Reason is not the correct explanation of the Assertion.
2. If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
3. If Assertion is true but Reason is false.
4. If both Assertion and Reason are false.

Answer: (a)

Methane is produced by incomplete biomass combustion, incomplete decomposition mostly by anaerobic methanogens.

Carbon dioxide contributes about 60% of the total global warming and share of methane ($CH_{4}$) and chlorofluorocarbons (CFCs) is 20% and 14% respectively. $N_{2}$O also contributes 6% in total global warming. Efficient engine such as multi point fuel injection engine can reduce the unburnt hydrocarbon (methane) in auto-emissions.

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Q34. Acid rain is caused by increase in the atmospheric concentration of :

1. $SO_{2}$ and $NO_{2}$
2. $O_{3}$ and dust
3. $SO_{3}$ and CO
4. $CO_{2}$ and CO

Answer: (a)

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Q35. Which of the following is not a greenhouse gas?

1. $CO_{2}$
2. $O_{2}$
3. $N_{2}$O
4. $CH_{4}$

Answer: (b)

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Q36. Montreal Protocol aims at

1. Control of $CO_{2}$ emission
2. Control of water pollution
3. Reduction of ozone depleting substances
4. Biodiversity conservation

Answer: (c)

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Q37. Match the columns.

1. A:2, B:3, C:1, D:4
2. A:2, B:3, C:4, D:1
3. A:4, B:3, C:2, D:1
4. A:4, B:3, C:1, D:2

Answer: (a)

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Q38. What percentage of solar radiation is reflected in the outer space by trophosphere?

1. 17%
2. 10%
3. 34%
4. 90%

Answer: (c)

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Q39. Why is the concentration of ozone less over the north and south poles?

1. CFC use is highest in these areas
2. CFCs accumulate only in area where the air is cold
3. CFCs stick to frozen water vapour and are able to act catalysts
4. UV rays are stronger in the atmosphere

Answer: (c)

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Q40. What happens to sewage water from the point of sewage discharge?

1. Mortality of fish ↑eses
2. Dissolved oxygen ↓eses
3. Biological oxygen demand ↑eses
4. All of these

Answer: (d)

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Q41. How deep should nuclear waste after sufficient pre-treatment be buried (in shielded containers) within the rocks below the earth's surface?

1. 200 m
2. 100 m
3. 300 m
4. 500 m

Answer: (d)

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Q42. Which one of the following expanded forms of the following acronyms is correct?

1. EPA-Environmental Pollution Agency
2. UNEP-United Nations Environmental Policy
3. IUCN-International Union for Conservation of Nature and Natural Resources
4. IPCC-International Penal for Climate Change

Answer: (c)

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Q43. The two great industrial tragedies namely, MIC and Chernobyl tragedies respectively occurred where and at which time?

1. Bhopal 1986, Russia 1988
2. Bhopal 1984, Ukraine 1986
3. Bhopal 1984, Ukraine 1990
4. Bhopal 1984, Ukraine 1988

Answer: (b)

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Q44. Carbon dioxide is called greenhouse gas because it is

1. transparent to heat but traps sunlight
2. used in greenhouse to increase plant growth
3. transparent to sunlight but traps heat
4. transparent to both sunlight and heat

Answer: (c)

The excess amount of $CO_2$ forms a thick 'blanket' in the atmosphere, which is transparent to sunlight, but absorbs infrared radiations trapping heat near the earth's surface. In this way, due to the $CO_2$ blanket, the earth's atmosphere works very much like a greenhouse, which causes warming up of the interiors. So, carbon dioxide is called a greenhouse gas.

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Q45. Which statement correctly represents the harmful effects of depletion of earth's ozone layer?

1. The oxygen content of the atmosphere will decrease
2. The average temperature of earth's surface will increase gradually
3. Increased amount of ultraviolet radiation will reach earth's surface
4. Sea levels will rise as the polar ice caps will gradually melt

Answer: (c)

This statement is correctly represents the harmful effects of depletion of earth's ozone layer.

On the other hand, statements in options (a), (b) and (d) represent the harmful effects of global warming.

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Q46. Choose the incorrect statement.

1. Methane and carbon dioxide are greenhouse gases
2. The Montreal protocol is associated with the control of emission of ozone depleting substances
3. Dobson units are used to measure oxygen content of air
4. Use of incinerators is crucial to disposal of hospital wastes

Answer: (c)

The incorrect statement be corrected as

Dobson unit is used to measure the thickness of the ozone layer in a column of air from the ground to the top of the atmosphere. On the other hand, oxygen sensors are used to measure the exhaust gas concentration of oxygen. Rest of the statements are correct.

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Q47. Match column-I with column-II and select the correct option.

Codes:

1. A – II, B – I, C – III, D – IV
2. A – I, B – II, C – III, D – IV
3. A – IV, B – III, C – II, D – I
4. A – III, B – II, C – IV, D – I

Answer: (a)

Catalytic converter is a device incorporated in the exhaust system of a motor vehicle, containing a catalyst for converting pollutant gases into less harmful ones. As the exhaust passes through the converter, unburnt hydrocarbons are converted into carbon dioxide, water, carbon monoxide and nitric oxide are changed to carbon dioxide and nitrogen gas respectively.

Electrostatic precipitator is a device that removes suspended dust particles from a gas or exhaust by applying a high-voltage electrostatic charge and collect the particles on charged plates.

Earmuffs is a pair of soft fabric coverings, connected by a band across the top of the head, that are worn over the ears to protect them from cold or high noise level.

Land - fill is a site for the disposal of solid waste in which refuse is buried between layers of dirt so as to fill in or reclaim low-lying ground.

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Q48. Fishes die by sewage because

1. It replaces food material of fishes
2. Of its bad smell
3. It increases oxygen competition among fishes
4. $CO_{2}$ is mixed in large amounts in water

Answer: (c)

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Q49. It is said, the Taj Mahal may be destroyed due to

1. Decomposition of marble as a result of high temperature
2. Flood in Yamuna river
3. Air pollutants released from oil refinery of Mathura
4. All of the above

Answer: (c)

Yellowing and blackening of Taj Mahal at Agra is due to $SO_2$ and other pollutants released by Mathura refinery.

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Q50. If the forest cover is reduced to half, what is most likely to happen on a long term basis?

1. Cattle in these and adjoining areas will die due to lack of fodder.
2. Tribals living in these areas will starve to death.
3. Large areas will become deserts.
4. Crop breeding programmes will suffer due to a reduced availability of variety of germplasm.

Answer: (c)

If the forest cover is reduced to half, large areas will become deserts, on a long term basis.

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Q51. ‘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.

1. They are called composting toilets.
2. Recycled human waste from this can be used as a natural fertilizer.
3. They do not depend on water for the disposal of excreta.
4. All of the above

Answer: (d)

All the statements regarding Eco San are correct. Eco san is a sustainable system for handling human excreta or faecal matter by using composting toilets. These are very useful in the rural areas where sewer system are not possible. These toilets are hygienic, efficient, practical and most effective for the disposal of human excreta.

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Q52. Fill up the blanks.

1. ...A...in soil results from irrigation without proper drainage of water. This affects the plants and draws salts to the soil surface. The salt is either deposited as a layer on land surface or collects at ...B... of plants.
2. A water logged soil has poor ...C... .
3. Removal of forest areas to fulfil the need of growing human population is called ...D... .
4. ...E... of India has recommended 33% forest cover for the plains and 67% for the hills.

Here A-E refers to

1. A–Water logging, B–roots, C–aeration, D–deforestation, E–The National Forest Policy (1988)
2. A–Soil erosion, B–stems, C–structure, D–reforestation, E–The National Forest Policy (1987)
3. A–Soil succession, B–leaves, C–nutrients, D–afforestation, E–The National Forest Policy (1989)
4. A–Desertification, B–fruits, C–minerals, D–deforestation, E–The National Forest Policy (1986)

Answer: (a)

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Q53. Which one of the following is not a bioindicator of water pollution ?

1. Blood worms
2. Sludge worms
3. Stone flies
4. Sewage fungus

Answer: (c)

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Q54. Match the following columns.

Codes A B C D

1. 4 3 2 1
2. 3 4 2 1
3. 2 3 4 1
4. 1 4 2 3

Answer: (b)

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Q55. Kyoto protocol was endorsed at

1. CoP - 4
2. CoP - 6
3. CoP - 3
4. CoP - 5.

Answer: (c)

Kyoto protocol is an international treaty to reduce emission of greenhouse gases which was adopted at the third session of the Conference of Parties (CoP - 3) to the UNFCCC (United Nations Framework Convention on Climate Change) in 1997, in Kyoto, Japan.

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Q56. Which one of the following is a wrong statement

1. Eutrophication is a natural phenomenon in freshwater bodies
2. Greenhouse effect is a natural phenomenon
3. Most of the forests have been lost in tropical areas
4. Ozone in upper part of atmosphere is harmful to animals

Answer: (d)

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Q57. Joint Forest Management Concept was introduced in India during

1. 1970 s
2. 1960 s
3. 1980 s
4. 1990 s

Answer: (c)

Joint Forest Management originated in West Bengal accidentally at the Arabari Forest Range in West Midnapore, near Midnapore town in 1971. After the initial successes in West Bengal and Haryana, the JFM schemes received national importance in the legislation of 1988.

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Q58. Kyoto Protocol was endorsed at:

1. CoP - 6
2. CoP - 5
3. CoP - 4
4. CoP – 3

Answer: (d)

In year 1997, at the conference of parties III (CoP - 3) ,Kyoto, Japan the Kyoto conference on climate change took place. In that conference developed countries agreed to specific targets for cutting their emissions of greenhouse gases. A general framework has been defined for this with specifics to be detailed in next few years. This become known as the Kyoto protocol.

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Q59. To improve the quality of environment (air, water and soil) the Govt. of India passed the ‘Environment (Protection) Act’ in year

1. 1986
2. 1981
3. 1987
4. 1974

Answer: (a)

Pollution is any undesirable change in physical chemical or biological characteristics of air, land, water or soil. In order to control environmental pollution, the Govt. of India has passed the Environment (Protection) Act, 1986 to protect and improve the quality of our environment.

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Q60. Why is it necessary to remove sulphur from petroleum products?

1. To increase efficiency of automobiles engines
2. To reduce the emission of sulphur dioxide in exhaust fumes
3. To use sulphur removed from petroleum for commercial purposes
4. To increase the life span of engine silencers

Answer: (b)

Removal of sulphur from petroleum product (diesel)reduces the emission of sulphur oxides like $SO_{2}$ and $SO_{3}$ in the exhaust fumes.

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Q61. 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

1. 1 April 2009
2. 1 April 2008
3. 1 April 2010
4. 1 April 2012

Answer: (c)

All automobiles and fuel - petrol and diesel were to meet the Euro III emission specification in some cities from 1 April 2008 and have to meet the Euro IV norms by 1 April 2010.

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Q62. Catalytic converters possesses which one of the following metals as catalyst?

1. Palladium
2. Platinum
3. Rhodium
4. All of these

Answer: (d)

Catalytic converters having expensive metals like platinum, palladium and rhodium as the catalysts, are fitted in automobiles for reducing the emission of poisonous gases like NO and CO. As it converts carbon monoxide (CO) and nitric oxide (NO) to less harmful gases, i.e. carbon dioxide and nitrogen gas.

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Q63. PM 2.5 or less than that in diameter in air causes

1. Damage to lungs
2. Irritation and inflammation in lungs
3. Premature deaths
4. All of these

Answer: (d)

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Q64. The toxic effect of carbon monoxide is due to its greater affinity for haemoglobin as compared to oxygen approximately by

1. 1000 times
2. 200 times
3. 2 times
4. 20 times

Answer: (b)

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Q65. Biochemical Oxygen Demand (BOD) may not be a good index for pollution for water bodies receiving effluents from

1. Petroleum industry
2. Dairy industry
3. Sugar industry
4. Domestic sewage

Answer: (a)

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Q66. Catalytic converters are fit into automobiles to reduce emission of harmful gases. Catalytic converters change unburnt hydrocarbons into

1. carbon monoxide
2. carbon dioxide and water
3. methane
4. carbon dioxide and methane

Answer: (b)

Catalytic converters contain costly metals like rhodium, platinum and palladium which act as catalysts and when exhaust gas passed through the fit catalytic converter, the unburnt hydrocarbons (cause of cancer) are oxidised into carbon dioxide and water.

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Q67. dB is a standard abbreviation used for the quantitative expression of

1. a particular pollutant
2. the density of bacteria in a medium
3. the dominant Bacillusin a culture
4. a certain pesticide.

Answer: (a)

Unwanted sound is called noise and it is measured in terms of decibels (dB). Generally sound above 80 dB is noise.

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Q68. Which one of the following is not used for disinfection of drinking water?

1. Ozone
2. Chlorine
3. Chloramine
4. Phenyl

Answer: (d)

In a sewage efficient treatment plant (CETP) during the tertiary treatment the decreased water is chlorinated with chlorine or perchlorate salts, ozonised or irradiate with UV to kill pathogens. Phenyl is not used for disinfection of drinking water.

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Q69. The metal used in catalytic converter in automobiles is

1. Palladium
2. Platinum
3. Rhodium
4. Any of these

Answer: (d)

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Q70. A feature of integrated organic farming is that

1. industrial wastes are utilised for manufacturing products like polyblend
2. in this process, waste products from one process are recycled and used as nutrients for other processes
3. chemical fertilisers are used to increase yield
4. Both (b) and (c)

Answer: (b)

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Q71. In Minamata Bay of Japan, the animals which remained free from Minamata disease, are

1. rabbits
2. pigs
3. dogs
4. cats

Answer: (a)

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Q72. Match the following columns and choose the correct option.

Codes A B C D

1. 1 3 2 4
2. 3 4 1 2
3. 4 1 2 3
4. 3 4 2 1

Answer: (b)

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Q73. Assertion (A): Ozone formed in the stratosphere by photochemical reactions as a result of human activities is harmful for all living organisms.

Reason (R): Ozone layer present in the troposphere is bad ozone.

1. If both A and R are true, but R is not the correct explanation of A
2. If both A and R are true and R is the correct explanation of A
3. If A is true, but R is false
4. If A is false, but R is true

Answer: (d)

Assertion is false, but Reason is true and Assertion can be corrected as

Good ozone is formed in stratosphere and absorbs harmful UV-radiations from the sun. Bad ozone is formed in troposphere and is harmful to plants and animals.

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Q74. Ultraviolet radiations from sunlight cause a reaction which produces

1. $SO_{2}$
2. $O_{3}$
3. CO
4. $CH_{4}$

Answer: (b)

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Q75. FOAM (Friends of the Arcata Marsh) is a group of citizens responsible for the integrated process of

1. sewage and water treatment
2. reducing eutrophication
3. radio-active waste treatment
4. minimizing global warming

Answer: (a)

Friends of the Arcata Marsh (FOAM) is a non-profit organization which for the last twenty years has advanced knowledge and educated the public about treatment and reuse of wastewater.

The purpose of the FOAM is to stimulate understanding of the Arcata Marsh and Wildlife Sanctuary, its relationship with Arcata's integrated wastewater treatment system, the surrounding watersheds and bay, and their link with the earth's water cycle.

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Q76. Which one of the following is being tried in India as a biofuels substitute for fossil fuels?

1. Azadirachta
2. Jatropha
3. Musa
4. Aegilops

Answer: (b)

Azadirachta is being tried in India as a biofuel substitute for fossil fuels. Bio fuels are the fuels of biological origin. They constitute renewable form of energy. Energy problems can be solved up to a great extent by efficient and proper used of these biofuels.

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Q77. Lichens indicate $SO_{2}$ pollution because they

1. grow faster than others
2. show association between algae and fungi
3. are sensitive to $SO_{2}$
4. flourish in $SO_{2}$ rich environment

Answer: (c)

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Q78. Which one of the following is not correct with regard to the harmful effects of particulate matter of the size 2.5 micrometer or less?

1. It can directly enter into our circulatory system.
2. It can cause respiratory problems.
3. It can cause inflammation and damage to the lungs.
4. It can be inhaled into the lungs.

Answer: (a)

Particulate matter consists of soot, flyash, dust, spores, pollen grains etc. Particulate matter is differentiated into settleable (larger than 10 mm and remaining in air for less than one day) and suspended (less than 10 mm and remaining in air for more than one day to several weeks). Particles of 2.5 µm and lesser diameter (PM 2.5) are the most harmful to human health (as per Central Pollution Control Board or CPCB).

They pass deep into the lungs causing breathing and respiratory problems, irritation, inflammation and damage to lungs resulting in pre-mature death. It cannot directly enter circulatory system but indirectly through respiratory system.

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Q79. Ultraviolet radiations from sunlight causes a reaction that produces

1. carbon monoxide
2. fluorides
3. sulphur dioxide
4. ozone.

Answer: (d)

Ozone is generated in the lower atmosphere during the formation of photochemical smog when nitrogen dioxide splits to produce reactive oxygen atoms which combine with molecular oxygen. Oxygen molecules split under ultraviolet radiations to produce oxygen atoms which combine with molecular oxygen to form ozone.

It is this gas which forms the protective ozone umbrella in the stratosphere and shield life from biocidal high energy radiations. It can also damage DNA molecules and cause carcinogenesis.

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Q80. If an agricultural field is liberally irrigated for a prolonged period of time, it is likely to face problem of

1. alkalinity
2. metal toxicity
3. acidity
4. salinity

Answer: (d)

Salinity of soil is a problem faced by farmers if they liberally irrigate agricultural field for a prolonged period.

Irrigation salinity is the accumulation of salts in the topsoil under irrigation. It is caused by over irrigation of agricultural land, inefficient water use, poor drainage and the irrigation of unsuitable and leaky soils.

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Q81. Which one of the following pair is mismatched?

1. Fossil fuel burning — Release of $CO_{2}$
2. Biomass burning — Release of $CO_{2}$
3. Nuclear power — Radioactive wastes
4. Solar energy — Green-house effect

Answer: (d)

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Q82. In an aquatic ecosystem, maximum biomagnification is seen among

1. phytoplanktons
2. fishes
3. microscopic plant
4. zooplanktons

Answer: (b)

Biomagnification refers to the increase in the concentration of a persistent chemical by the organisms at successive trophic levels in a food chain. The maximum biomagnification is seen among fishes in an aquatic ecosystem.

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Q83. Which one of the following statements is not valid for aerosols?

1. They cause increased agricultural productivity.
2. They alter rainfall and monsoon patterns.
3. They have negative impact on agricultural land.
4. They are harmful to human health

Answer: (a)

Aerosols are harmful environmental pollutants which have negative effects on agriculture.

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Q84. Who prepared polyblend?

1. Ramesh Chand Dagar
2. Ahmed Khan
3. Amrita Devi
4. Sunderlal Bahuguna

Answer: (b)

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Q85. Assertion (A): Methane component of greenhouse gases contributing to global warming is about 20%.

Reason (R): Introduction of multi-point fuel injection engines in automobiles has increased methane content in the exhausts.

1. If both A and R are true, but R is not the correct explanation of A
2. If both A and R are true and R is the correct explanation of A
3. If A is true, but R is false
4. If A is false, but R is true

Answer: (c)

Assertion is true, but Reason is false. Reason can be corrected as

Introduction of efficient engines in automobiles such as multi-point fuel injection engine have reduced the unburnt hydrocarbon (methane) content in the exhausts.

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Q86. Compressed Natural Gas (CNG) is

1. methane
2. propane
3. ethane
4. butane

Answer: (a)

Compressed Natural Gas (CNG) is the best, cheap fuel, that has replaced petrol and diesel fuel and is considered as clean fuel. it consists of around 90% methane, by compressing it to less than 1% of volume it occupies at standard atmospheric pressure.

Propane and butane together form LPG or liquified petroleum gas while ethane is used in chemical industry to produce ethene.

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Q87. Find the incorrect statement.

1. Seepage of chemical from landfills pollutes the underground water resources.
2. Sanitary landfills were adopted as the substitute for open burning dumps.
3. All waste that we generate can be categorized into three types, i.e., bio-degradable, recyclable and non-biodegradable.
4. Open dumps inhibit breeding of rats and flies.

Answer: (d)

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Q88. Which of the following is the use of lichens in case of pollution?

1. Lichens are not related with pollution.
2. They promote pollution.
3. They treat the polluted water.
4. They act as bioindicators of pollutions

Answer: (d)

Lichens are very sensitive to $SO_2$ pollution. They do not grow in $SO_2$ polluted environment.

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Q89. The use of DDT is banned now a days because it is

1. Note available
2. Very costly
3. Inflammable
4. Not degraded easily

Answer: (d)

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Q90. Acid rain is caused by increase in the atmospheric concentration of

1. $O_3$ and dust
2. $CO_2$ and CO
3. $SO_2$ and $NO_2$
4. $SO_3$ and CO

Answer: (c)

Acid rain is rainfall and other forms of precipitation with a pH of less than 5. Acid rain is caused by large scale emission of acidic gases into the atmosphere from thermal power plants, industries and automobiles.

The common ones are sulphur dioxide, nitrogen oxides ($NO_x$), volatile organic carbons (VOCs) and hydrogen chloride. Sulphur dioxide and nitrogen oxides are changed in the atmosphere into sulphuric acid and nitric acid by combining with oxygen and water, which then fall on earth in the form of acid rain.

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Q91. If the forest cover is reduced to half, what is most likely to happen on a long term basis?

1. Cattle in these and adjoining areas will die due to lack of fodder
2. Tribals living in these areas will starve to death
3. Large areas will become deserts
4. Crop breeding programmes will suffer due to a reduced availability of variety of germplasm

Answer: (c)

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Q92. Which of the following is the main factor of desertification?

1. Tourism
2. Over-grazing
3. Irrigated agriculture
4. All of these

Answer: (b)

Desertification means a process of spread of desert that occurs due to degradation of environment, cutting of trees, soil erosion, etc. It can be natural or man made. The main causes for desertification are overcultivation of poor soils, over grazing by animals, excessive cutting of fuel wood and inappropriate irrigation practises resulting in salinization. Among them overgrazing is the most important factor as it causes maximum effect.

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Q93. _________ are used in electrostatic precipitator. Choose the most appropriate option to fill in the blank.

1. Absorbers
2. Catalysts
3. Electrodes
4. Chemicals

Answer: (c)

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Q94. Today the concentration of greenhouse gases is very high because of

1. increased combustion of oils and coal.
2. use of refrigerator.
3. deforestation.
4. all of the above

Answer: (d)

Greenhouse gases contribute to the greenhouse effect by absorbing infrared radiation. Greenhouse gases in the earth's atmosphere absorb IR from the sun and release it. Some of the heat released reaches the earth, along with heat from the sun that has penetrated the atmosphere. Both the solar heat and the radiated heat are absorbed by the earth and released; some are reabsorbed by greenhouse gases to preserve the cycle.

Common examples of greenhouse gases include: water vapour, carbon dioxide, methane, nitrous oxide, ozone, and any fluorocarbons. Although water vapour is the most abundant greenhouse gas but it is a relatively ineffective one.

Human activities are responsible for almost all of the increase in greenhouse gases in the atmosphere over the last 150 years. Today the concentration of greenhouse gases is very high because of use of refrigerator, increased combustion of oils and coal and deforestation.

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Q95. dB is a standard abbreviation used for the quantitative expression of

1. A particular pollutant
2. The density of bacteria in a medium
3. The dominant bacillus in a culture
4. A certain pesticide

Answer: (a)

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Q96. As a result of global warming, the sea level will

1. decrease
2. increase
3. remain the same
4. none of these

Answer: (b)

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Q97. The air prevention and control of pollution act came into force in

1. 1990
2. 1985
3. 1975
4. 1981

Answer: (d)

Air (Prevention and control of pollution) Act came into force in 1981, but was amended in 1987 to include noise as an air pollutant.

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Q98. In 1984, Bhopal gas tragedy was caused due to leakage of

1. methyl isocyanate
2. potassium isocyanate
3. sodium monoxide
4. none of these

Answer: (a)

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Q99. Montreal Protocol aims at

1. control of water pollution
2. biodiversity conservation
3. control of CO 2 emission
4. reduction of ozone depleting substances.

Answer: (d)

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Q100. The scrubber is used mainly to remove the following gas/es from the exhaust after spraying water/ lime

1. $SO_{2}$
2. $CO_{2}$
3. $O_{2} & N_{2}$
4. CO & $CO_{2}$

Answer: (a)

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