Answer:
Option (4)
Explanation:
Fossils are the dead remnants of ancient flora and fauna that are buried millions of years ago. These fossils are found to be embedded in the sedimentary rocks. Fossils are important because they help in determining the age of the rocks.
The fossils are often dated by different radioactive dating methods, that have different half-lives.
Radioactive dating methods are defined as the methods that determine the age of the rocks and other objects by dating them. The decay rate of these radioactive isotopes must be known to calculate the age. For example, the Carbon-14 dating method.
These fossils are very much helpful because different fossils belong to different time periods. By dating these fossils and the rocks containing them (including other astronomical bodies), one can determine the age of them. The age of the earth is also estimated by using these radioactive dating methods.
Hence, the correct answer is option (4).
