21. Biodegradable waste can be:
A) Decomposed
B) Not decomposed
C) Permanent
D) Toxic
Answer: A
22. Non-biodegradable waste includes:
A) Food waste
B) Paper
C) Plastic
D) Leaves
Answer: C
23. Which is a renewable resource?
A) Coal
B) Petroleum
C) Solar energy
D) Natural gas
Answer: C
24. Which is non-renewable?
A) Wind
B) Water
C) Coal
D) Sunlight
Answer: C
25. The main source of air pollution is:
A) Plants
B) Vehicles
C) Water
D) Soil
Answer: B
26. Global warming leads to:
A) Cooling
B) Ice formation
C) Rise in temperature
D) Rainfall decrease
Answer: C
27. Which gas is most abundant greenhouse gas?
A) CO₂
B) Methane
C) Water vapor
D) Ozone
Answer: C
28. Methane is produced by:
A) Factories
B) Rice fields
C) Cars
D) Oceans
Answer: B
29. Lead pollution comes from:
A) Water
B) Petrol
C) Oxygen
D) Plants
Answer: B
30. Which metal is toxic?
A) Iron
B) Lead
C) Calcium
D) Sodium
Answer: B