11. Which of the following pollutants is the major cause of respiratory diseases in urban areas?
A) Lead
B) Carbon monoxide
C) Particulate matter (PM2.5)
D) Methane
Answer: C) Particulate matter (PM2.5)
Explanation:
Fine particulate matter (PM2.5) can penetrate deep into the lungs and even enter the bloodstream. It is a significant cause of respiratory problems like asthma, bronchitis, and lung cancer, especially in urban areas with high traffic and industrial activity.
12. Minamata disease is caused by the poisoning of which heavy metal?
A) Lead
B) Arsenic
C) Mercury
D) Cadmium
Answer: C) Mercury
Explanation:
Minamata disease is a neurological syndrome caused by severe mercury poisoning. It was first discovered in Minamata, Japan, and resulted from industrial discharge of methylmercury into water bodies, which then accumulated in fish and shellfish consumed by the local population.
13. Which of the following is a biodegradable pollutant?
A) DDT
B) Plastic
C) Paper
D) Polythene bags
Answer: C) Paper
Explanation:
Biodegradable pollutants are those that can be broken down by natural processes. Paper is a biodegradable material because it decomposes through the action of bacteria and other organisms. DDT, plastic, and polythene bags are non-biodegradable and persist in the environment for a long time.
14. Which method is commonly used for the treatment of domestic wastewater?
A) Incineration
B) Electrostatic precipitation
C) Sedimentation and filtration
D) Pyrolysis
Answer: C) Sedimentation and filtration
Explanation:
Sedimentation and filtration are the primary methods used in the treatment of domestic wastewater. In sedimentation, heavier particles settle down, while in filtration, the water passes through filters to remove smaller impurities.
15. Which of the following statements about greenhouse gases is incorrect?
A) Carbon dioxide is a greenhouse gas.
B) Greenhouse gases trap heat in the atmosphere.
C) Nitrous oxide is not a greenhouse gas.
D) Methane is a greenhouse gas.
Answer: C) Nitrous oxide is not a greenhouse gas
Explanation:
This statement is incorrect because nitrous oxide (N₂O) is indeed a greenhouse gas. It contributes to the greenhouse effect by trapping heat in the Earth’s atmosphere, along with other gases like CO₂ and methane.
16. The “Bhopal Gas Tragedy” involved the accidental release of which toxic gas?
A) Carbon monoxide
B) Methane
C) Methyl isocyanate
D) Ammonia
Answer: C) Methyl isocyanate
Explanation:
The Bhopal Gas Tragedy occurred in 1984 when methyl isocyanate gas leaked from a pesticide plant in Bhopal, India. This gas is highly toxic and caused widespread death and illness in the local population.
17. Which of the following pollutants can cause the formation of photochemical smog?
A) Nitrogen oxides and hydrocarbons
B) Carbon dioxide and oxygen
C) Sulfur dioxide and water vapor
D) Particulate matter and methane
Answer: A) Nitrogen oxides and hydrocarbons
Explanation:
Photochemical smog forms when nitrogen oxides (NOx) and volatile organic compounds (VOCs) like hydrocarbons react in the presence of sunlight. This leads to the production of harmful secondary pollutants, such as ozone (O₃), which contribute to respiratory problems and environmental damage.
18. Which pollutant is commonly associated with acid rain?
A) Ozone
B) Nitrogen dioxide
C) Carbon dioxide
D) Methane
Answer: B) Nitrogen dioxide
Explanation:
Nitrogen dioxide (NO₂), along with sulfur dioxide (SO₂), is one of the primary pollutants responsible for acid rain. These gases react with water vapor in the atmosphere to form nitric and sulfuric acids, which fall as acid rain.
19. Which of the following is a major source of water pollution in rivers in India?
A) Agricultural runoff
B) Oil spills
C) Eutrophication
D) Thermal pollution
Answer: A) Agricultural runoff
Explanation:
Agricultural runoff, containing pesticides, fertilizers, and other chemicals, is a major source of water pollution in rivers in India. These pollutants lead to eutrophication, contamination of drinking water, and loss of biodiversity in aquatic ecosystems.
20. Which of the following best defines biomagnification?
A) The accumulation of pollutants in the water
B) The process of increasing pollutant concentration at higher trophic levels
C) The filtration of pollutants by plants
D) The breakdown of pollutants in the environment
Answer: B) The process of increasing pollutant concentration at higher trophic levels
Explanation:
Biomagnification refers to the increasing concentration of toxic substances like heavy metals or pesticides as they move up the food chain. Organisms at higher trophic levels accumulate higher concentrations of these pollutants, posing serious health risks.
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