Dear Student,
Fuels that are formed from the dead remains of living organisms by natural processes are called fossil fuels. They take millions of years to form.
Petroleum, coal and natural gas are fossil fuels, which are formed after dead remains of living organisms get buried under the sea and earth through natural processes like compression.
Yes fossil fuels are also a type of natural resources. as they are derived from the living things or organic materials, that is the biotic resources.
Regards