Here's a breakdown:

* Coal: Formed from dead plants that accumulated in swamps and were buried under layers of sediment. Over millions of years, heat and pressure transformed the plant matter into coal.

* Oil and Natural Gas: Formed from marine organisms like algae and plankton that died and settled at the bottom of the ocean. They were buried under layers of sediment and, under heat and pressure, transformed into oil and natural gas.

Key Components:

* Carbon: The primary element in fossil fuels, originally from the organic matter.

* Hydrogen: Another significant component, also originating from the organic matter.

* Other elements: Small amounts of sulfur, nitrogen, oxygen, and trace minerals.

Formation Process:

1. Deposition: Organic matter accumulates in a suitable environment.

2. Burial: Layers of sediment bury the organic matter.

3. Heat and Pressure: As layers of sediment accumulate, heat and pressure increase, transforming the organic matter into fossil fuels.

It's important to remember that fossil fuels took millions of years to form, making them a non-renewable resource.