by the contamination of drinking water with sewage when tje pipes for the transportation of drinking water and disposal of sewage are drawn together in cities
It is the Archean Eon! :)
The correct answer is precipitation.
Fossils are important for working out the relative ages of sedimentary rocks. Fossils can help to match rocks of the same age, even when you find those rocks a long way apart. This matching process is called correlation, which has been an important process in constructing geological timescales. Relative dating is also used to arrange geological events, and the rocks they leave behind, in a sequence.
