91. Which pollutant causes skin cancer?
A) UV radiation
B) Oxygen
C) Nitrogen
D) Hydrogen
Answer: A
92. Which gas is used in refrigeration causing ozone depletion?
A) CFC
B) CO₂
C) O₂
D) N₂
Answer: A
93. The main source of sulfur dioxide is:
A) Burning fossil fuels
B) Plants
C) Water
D) Soil
Answer: A
94. Which process reduces air pollution?
A) Planting trees
B) Cutting trees
C) Burning waste
D) Smoking
Answer: A
95. Which pollutant causes eye irritation?
A) Ozone
B) Oxygen
C) Nitrogen
D) Hydrogen
Answer: A
96. Which is a secondary treatment of wastewater?
A) Filtration
B) Biological treatment
C) Sedimentation
D) Screening
Answer: B
97. Which pollutant causes corrosion of metals?
A) Acid rain
B) Oxygen
C) Nitrogen
D) Hydrogen
Answer: A
98. Which is a source of radioactive pollution?
A) Nuclear waste
B) Plants
C) Water
D) Soil
Answer: A
99. Which gas contributes to smog formation?
A) NOx
B) O₂
C) N₂
D) H₂
Answer: A
100. Sustainable development means:
A) Use resources wisely
B) Overuse resources
C) Destroy environment
D) Ignore future
Answer: A