41. Smog is a mixture of:
A) Smoke and fog
B) Water and air
C) Gas and dust
D) None
Answer: A
42. Which is a secondary pollutant?
A) CO
B) NO₂
C) Ozone
D) SO₂
Answer: C
43. Which gas is used in photosynthesis?
A) O₂
B) CO₂
C) N₂
D) H₂
Answer: B
44. Waste management includes:
A) Disposal
B) Recycling
C) Treatment
D) All
Answer: D
45. Which is not air pollutant?
A) CO₂
B) O₂
C) SO₂
D) NO₂
Answer: B
46. Which is the main cause of ozone depletion?
A) CO₂
B) CFCs
C) O₂
D) N₂
Answer: B
47. Thermal pollution affects:
A) Air
B) Soil
C) Water
D) Noise
Answer: C
48. Which sector contributes most to pollution?
A) Agriculture
B) Industry
C) Education
D) Health
Answer: B
49. pH of pure water is:
A) 5
B) 6
C) 7
D) 8
Answer: C
50. Environmental protection aims to:
A) Increase pollution
B) Destroy nature
C) Protect environment
D) Reduce oxygen
Answer: C