Carbon-14 is a radioactive form of carbon. carbon-12 is the most common type of carbon. the ratio of these two atoms stays constant in living things but changes after an organism dies since carbon-14 continues to decay while the amount of carbon-12 remains the same. the half-life of carbon-14 is nearly six-thousand years. if you found a bone that had no measureable amount of carbon-14 in it, what could you conclude about the animal the bone came from? a. it died recently. b. it died less than six-thousand years ago. c. it died more than six-thousand years ago. d. nothing, since more information is needed to answer this question.