Which of the following organisms are used as bio-indicators of sulphur dioxide pollution in the air?
- A.Lichens
- B.Earthworms
- C.Honey bees
- D.Water hyacinth
Correct answer
Explanation
The correct answer is A, Lichens. A lichen is a partnership of an alga and a fungus and takes its water and nutrients straight from the air, with no protective cuticle and no roots. It therefore absorbs dissolved sulphur dioxide along with moisture and dies even where the concentration is too low to harm most plants, so the disappearance of lichens from tree trunks in a city is read as a sign of sulphur dioxide pollution. Option B is wrong because earthworms indicate the health and moisture of soil. Option C is wrong because honey bees are watched as indicators of pesticide use and of the state of flowering plants. Option D is wrong because water hyacinth, the Bengal terror, indicates nutrient-rich polluted water rather than polluted air. Bio-indicator questions are best answered by asking which organism takes its living directly from the medium named, since that is the one which suffers first when the medium is fouled.
Read the full article: Air Pollution and Air Quality: Pollutants, AQI and Laws
Practice Questions
View allWhich of the following is a secondary air pollutant?
- A.Sulphur dioxide
- B.Carbon monoxide
- C.Peroxyacetyl nitrate
- D.Particulate matter
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A secondary pollutant is never emitted from a source; it is manufactured in the atmosphere itself when primary pollutants react with one another or with sunlight.
Read the full explanation →Which of the following is the chief component of photochemical smog?
- A.Sulphur dioxide
- B.Ozone
- C.Methane
- D.Carbon dioxide
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Photochemical smog, also called Los Angeles smog, forms in warm, dry, sunny weather when oxides of nitrogen from vehicle exhaust and unburnt hydrocarbons react under ultraviolet light.
Read the full explanation →Carbon monoxide is dangerous to human beings mainly because it:
- A.Combines with haemoglobin to form carboxyhaemoglobin
- B.Dissolves in water to form a strong acid
- C.Destroys the ozone layer of the stratosphere
- D.Settles in the alveoli as fine dust
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Carbon monoxide binds to the haemoglobin of the blood roughly two hundred times more readily than oxygen does, and the carboxyhaemoglobin so formed cannot carry oxygen.
Read the full explanation →Along with the oxides of nitrogen, which gas is chiefly responsible for acid rain?
- A.Carbon monoxide
- B.Methane
- C.Sulphur dioxide
- D.Argon
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Sulphur dioxide, released when coal and oil containing sulphur are burnt, is oxidised in the atmosphere to sulphur trioxide, which dissolves in water droplets to give sulphuric acid.
Read the full explanation →The damage to the marble of the Taj Mahal, popularly called 'marble cancer', is caused chiefly by:
- A.Carbon dioxide
- B.Sulphur dioxide
- C.Chlorofluorocarbons
- D.Ground-level ozone
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Sulphur dioxide from industry and traffic around Agra is oxidised in the air and comes down as sulphuric acid, which attacks the calcium carbonate of marble.
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