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The age of the fossil must be determined so it can be compared to other fossil species from the same time period.
The most widely known form of radiometric dating is carbon-14 dating.
This is what archaeologists use to determine the age of human-made artifacts. The half-life of carbon-14 is only 5,730 years, so carbon-14 dating is only effective on samples that are less than 50,000 years old.
Carbon is the 15th most abundant element in the Earth's crust, and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen.
Carbon's abundance, its unique diversity of organic compounds, and its unusual ability to form polymers at the temperatures commonly encountered on Earth enables this element to serve as a common element of all known life.
It involves the chemical reactions between chemical compounds in the atmosphere and chemical compounds on the planet's surface.