61. What is the process of converting coal into a solid fuel called?
a) Coal gasification
b) Coal liquefaction
c) Coalification
d) Carbonization
62. Which country is the largest exporter of liquefied natural gas (LNG) in the world?
a) Qatar
b) Australia
c) United States
d) Russia
63. What is the process of removing impurities, such as sulfur, from natural gas liquids called?
a) Sweetening
b) Purification
c) Refining
d) Fractionation
64. Which gas is added to natural gas pipelines to maintain pressure and ensure smooth transportation?
a) Oxygen
b) Carbon dioxide
c) Methane
d) Nitrogen
65. What is the term used to describe the process of converting biomass into biofuels, such as bioethanol or biodiesel?
a) Biomass conversion
b) Biomass gasification
c) Biomass liquefaction
d) Biomass pyrolysis
