Which of the following describes fossil fuels?

Fossil fuels are indeed energy sources that originate from ancient organic matter, specifically the remains of plants and animals that lived millions of years ago. Over time, these remains have undergone geological processes involving heat and pressure, transforming them into coal, oil, and natural gas. This transformation is a result of natural processes that occur over extensive periods, making fossil fuels a non-renewable resource, as they cannot be replenished within a human timeframe.

In contrast to other options, fossil fuels are not renewable energy sources derived from solar energy, as they require millions of years to form and are being depleted faster than they can be replaced. They are also not primary sources of atmospheric oxygen; in fact, their combustion releases carbon dioxide and other gases that contribute to pollution and climate change. Additionally, fossil fuels have a significant environmental impact due to emissions produced during extraction and burning, which contradicts the notion of having no impact on the environment. Therefore, the description of fossil fuels as energy sources from ancient organic matter captures their essence accurately.