61. Which pollutant affects visibility?
A) Smog
B) Oxygen
C) Nitrogen
D) Hydrogen
Answer: A
62. The greenhouse effect was discovered by:
A) Newton
B) Arrhenius
C) Dalton
D) Boyle
Answer: B
63. Which chemical is used in pesticides?
A) DDT
B) NaCl
C) H₂O
D) CO₂
Answer: A
64. Bioaccumulation refers to:
A) Decrease of toxins
B) Increase of toxins in organisms
C) Removal of toxins
D) None
Answer: B
65. Which pollutant causes blue baby syndrome?
A) Nitrates
B) Sulfates
C) Chlorides
D) Carbonates
Answer: A
66. The main source of indoor pollution is:
A) Plants
B) Cooking fuels
C) Oxygen
D) Water
Answer: B
67. Which is not a greenhouse gas?
A) CO₂
B) CH₄
C) N₂
D) Water vapor
Answer: C
68. The process of removing pollutants is called:
A) Pollution
B) Purification
C) Contamination
D) None
Answer: B
69. The main source of nitrogen oxides is:
A) Vehicles
B) Plants
C) Soil
D) Water
Answer: A
70. Which gas forms photochemical smog?
A) NO₂
B) O₂
C) H₂
D) He
Answer: A