* Fossil Fuels: Fossil fuels are formed from the remains of ancient organisms over millions of years. The three main types are coal, oil, and natural gas.

* Coke: Coke is a solid fuel made from coal by heating it in the absence of air. It's primarily used in the production of iron and steel.

* Natural Gas: Natural gas is a naturally occurring gas composed primarily of methane. It's a clean-burning fossil fuel often used for heating and electricity generation.

While coke is derived from a fossil fuel (coal), it is not a fossil fuel itself.