Answer:
Fossil fuels
Explanation:
Fossils are the remnants of the ancient plants and animals that were buried thousands and millions of years back. These fossils over a large geological time were subjected to the high pressure and temperature conditions, and are found to be embedded in the sedimentary rocks.
These fossil fuels are highly essential for use, but they are considered to be non-renewable resources as it takes a large amount of time for formation. The use of these fossil fuels must be reduced as it releases a high amount of carbon that is harmful to the environment.
