Solution:Concept: Fossil fuels are formed from the dead remains of plants. Sedimentary rock with a brownish-black tint called coal is flammable. Along with other elements including hydrogen, sulphur, oxygen, and nitrogen, coal primarily contains carbon.
Dead plant debris decomposes into peat, which then turns into coal. After being exposed to high temperatures and pressure while being buried for millions of years, peat eventually turns into coal.
Petroleum and natural gas are made from the remains of extinct marine animals like plants, algae, and bacteria, similar to how coal is created.
Because they were created from the buried remains of plants and microscopic animals that existed hundreds of millions of years ago, they are known as fossil fuels.
Hence, the correct answer is- because they are formed from dead remains.