Answer: b. remains of traces of prehistoric life
Fossils are the remains or traces that are found inside the deep layers of the earth crust. These are formed when the body of dead animals and plants are decomposed by the soil microbes. Some of the hard remains like bones, shells, wood and others are left. These remains get covered by the piles of the sediments. These sediments when compact forms rocks. These rocks exhibit fossils as reserves. These preserved fossils exhibit details of the structures and features that previously existing organisms might be possessing. Therefore, fossils are the remains of traces of prehistoric life.
