Here's a breakdown:
* Tiny Organisms: These were mainly phytoplankton and zooplankton, tiny plants and animals that lived in the ocean.
* Death and Sedimentation: Over millions of years, these organisms died and settled to the ocean floor, forming layers of sediment.
* Pressure and Heat: Over time, the weight of the sediment layers, combined with heat from the Earth's core, transformed the organic matter into fossil fuels.
* Fossil Fuels: This process created coal, oil, and natural gas, which are valuable energy sources today.
It's important to remember that this process takes a very long time, on the order of millions of years, to create fossil fuels.