Biology

The correct answer is D.fossil fuels.

Here’s why:

When organisms (such as plants and animals) do not decompose fully due to specific environmental conditions, they can be buried under layers of sediment. Over millions of years, heat and pressure transform these organic remains into fossil fuels, such as coal, oil, and natural gas. Fossil fuels are rich in carbon, which was originally part of the organisms' bodies before they were buried and subjected to geological processes.

Now, let’s clarify the other options:

A.Water: While water is essential for life and is involved in many natural processes, it is not formed from decomposing ...