Assertion: natural gas | /r/HasProperty | oil
Facets:
Source sentences:
text: Natural gas is a finite source of energy (exactly like coal and oil), but because natural gas was not used as the main energy source on the planet by now, and there are many other sites with reserves of natural gas that are undiscovered yet, we consider that this energy source is capable of successfully replace coal and oil as the main energy source on the planet for the following two or three decades.
text: Natural gas, coal, and petroleum (oil) are non-renewable energy sources that are called fossil fuels.
text: Natural gas is a fossil fuel, like oil and coal.