Correct Answer:
C. Carbon-14.
Carbon dating, a critical method in archaeology and paleontology, utilizes the naturally occurring radioactive isotope Carbon-14 (C-14). All living organisms absorb carbon from their environment, including a small, consistent amount of C-14. When an organism dies, it stops exchanging carbon, and the C-14 within its tissues begins to decay radioactively into Nitrogen-14. By precisely measuring the remaining ratio of C-14 to stable carbon isotopes (like C-12) in an organic sample, scientists can accurately estimate the time elapsed since the organism's death, providing dates for artifacts and fossils up to approximately 50,000 to 60,000 years old.
- Carbon-12: This is the most abundant and stable isotope of carbon. It does not undergo radioactive decay, so it cannot be used for dating purposes, though it serves as a crucial reference in the carbon dating process.
- Carbon-13: Another stable, non-radioactive isotope of carbon. While it is useful in isotopic analysis for studying ancient diets and environmental conditions, it does not decay and therefore cannot be used to determine age.
- Carbon-15: This is a highly unstable and extremely short-lived radioactive isotope of carbon with a half-life measured in milliseconds. Its rapid decay makes it entirely unsuitable for dating ancient organic materials, as it would vanish almost instantaneously.