How are fossils formed ? Describe, in brief, two methods of determining the age of fossils.

Formation of Fossils:

Fossils are the preserved remains, impressions, or traces of ancient organisms that lived millions of years ago. When an organism dies, its body usually decomposes completely. However, if the body or some of its hard parts (like bones, teeth, or shells) get buried in mud, silt, or volcanic ash where decomposition is extremely slow or prevented due to lack of oxygen, the sediments gradually harden into rock over millions of years. This preserves the hard parts or leaves a permanent impression of the organism's body in the rock.

Methods of Determining the Age of Fossils:

1. Relative Method: This method is based on the depth of the geological strata. When we dig into the earth, the fossils found in the layers closer to the surface are more recent, while those found in deeper, older layers of sediment are older.
2. Radioactive Dating (Carbon Dating): This method involves estimating the age of a fossil by measuring the ratio of different isotopes of the same element (such as radioactive carbon-14 to stable carbon-12) remaining in the fossil material, as radioactive isotopes decay at a known, constant rate.