How much parent nuclide remains after three half-lives have elapsed? A. 0% B. 6.25% C. 12.5% D. 30% 29. If a sample of radioactive material contains 17% daughter nuclide, what percentage of parent nuclide is present in the sample? A. 0% B. 17% C. 50% D. 83% 30. The isotope used to determine the absolute age of organic remains is A. carbon-14 B. carbon-12 C. uranium-235 D. uranium-238 31. The half-life of carbon-14 is 5730 years. How old is a bone fragment if the proportion of carbon-14 remaining is 25%? A. 2865 a B. 5760 a C. 11 460 a D. 17 190 a
