They are found underground, so they are FOSSIL fuels.
They have been formed over millions of years as dead animals and plants have been crushed and compressed by the weight of the ever-increasing material on top of them. Their age, along with the fact...
peat natural gas and many others
Both of them are because they evolved from little tiny creatures millions of years ago
Our Lives Without Fossil Fuels
Strategies to Reduce Global Fossil Fuel Consumption
Impact of Using Fossil Fuels in Alaska
Ending World Reliance on Fossil Fuels