OIL!
in its early stages this fossil fuel is a spongy brown material
coal
natural gas
No use of ANY fossil fuel can be regarded as conserving resources.
Coal provides about 40 percent of the world's energy supply. It is a major source of electricity generation in many countries, especially in Asia. However, coal is also a significant contributor to greenhouse gas emissions and air pollution.
The fossil fuel in question is likely coal, as it is one of the most abundant fossil fuels. With current consumption rates, estimates suggest that coal reserves could last for the next 200 years. However, environmental concerns and the shift towards renewable energy sources may impact the actual duration of coal reserves.
No its not a fossil fuel
Oil is a fossil fuel.
Fossil fuel is cheap
Fossil
In my opinion, when considering fossil fuels, coal provides the most pollution in terms of released and/or generated amount of CO2 because coal has a high amount of carbon in its fuel composition provided on the unit mass basis and it has the smallest stoichiometric oxidant to fuel ratio when ideal and complete combustion takes place.