Final answer:
Using Carbon-14 dating, a fossil with 68% of its original Carbon-14 is approximately one half-life, or around 5,730 years old; however, a precise age cannot be determined without more information.
Step-by-step explanation:
Carbon-14 Dating and the Age of a Fossil
Carbon-14 (C-14) dating is a method used to determine the age of ancient artifacts and fossils. This technique relies on measuring the ratio of radioactive carbon-14 to stable carbon-12 (C-12) in a sample to calculate how long it has been since the organism died. As C-14 has a half-life of approximately 5,730 years, a fossil with a C-14 level of 68% compared to living organisms is approximately one half-life old, which equates to roughly 5,730 years. However, without a precise measurement of the decay rate and initial C-14 concentration, an exact age determination is not achievable with the information provided.