How are "fossil fuels" formed?

Fossil fuels are formed from the ancient remains of plants and animals that lived millions of years ago. This process begins when organic matter from these organisms is buried under layers of sediment. Over time, heat and pressure from the overlying materials cause the organic material to undergo chemical transformation. This process, known as diagenesis, eventually leads to the formation of coal, oil, and natural gas.

The formation of fossil fuels is intricately tied to geological, chemical, and biological processes that convert the carbon-rich remains into the energy-dense materials we use today. The specific conditions—such as the type of vegetation, geological pressure, and temperature at the time of burial—play a crucial role in determining the type of fossil fuel that is produced.

Understanding this process highlights the importance of both geological time scales and ancient ecosystems in the formation of crucial energy resources. In contrast to the other options, this correct answer emphasizes the historical and biological origins of these fuels and their connection to prehistoric life on Earth.