Which property of carbon-14 allows scientists to use it for dating dead organisms?

• A. Its radioactive decay at a known rate enables determination of the time since death.
• B. Its abundance in living organisms increases after death.
• C. It forms stable compounds that preserve tissue indefinitely.
• D. Its atomic mass changes when organisms die.

Answer: (A)

Verified step by step guidance

1. Understand that carbon-14 is a radioactive isotope of carbon, meaning it undergoes radioactive decay over time.
2. Recognize that living organisms constantly exchange carbon with their environment, maintaining a steady level of carbon-14 while alive.
3. When an organism dies, it stops exchanging carbon, so the carbon-14 it contains begins to decay without being replenished.
4. The rate of decay of carbon-14 is known and characterized by its half-life, which allows scientists to calculate how much time has passed since the organism's death.
5. Therefore, the key property used for dating is the predictable radioactive decay of carbon-14, which acts as a clock to determine the time elapsed since death.