31. What is the term used to describe the outermost layer of the Earth?
A) Mantle
B) Crust
C) Core
D) Lithosphere
Answer: B) Crust
32. Which of the following is not a type of rock?
A) Igneous
B) Metamorphic
C) Sedimentary
D) Granitic
Answer: D) Granitic
33. What is the term used to describe the process of removing salt from seawater to make it drinkable?
A) Desalination
B) Filtration
C) Distillation
D) Purification
Answer: A) Desalination
34. Which of the following is not a type of renewable energy?
A) Solar
B) Wind
C) Coal
D) Hydroelectric
Answer: C) Coal
35. What is the term used to describe the process of using microorganisms to break down organic matter and convert it into biogas?
A) Anaerobic digestion
B) Fermentation
C) Incineration
D) Combustion
Answer: A) Anaerobic digestion
