Answer:
Radioactive dating
Step-by-step explanation:
Radioactive dating measures the ratio of C¹²(normal) and C¹⁴ (radioactive) in fossils to determine the exact age of the specimen. C¹⁴ is unstable and has a half life of 5730 years, so as the organism ages the amount of C¹⁴ diminishes but the amount of C¹² remains constant. The ratio of C¹⁴ to C¹² is used to analyze the decay of atomic particles to determine exact age.