The decay of radioactive elements occurs at a fixed rate. The half-life of a radioisotope is the time required for one half of the amount of unstable material to degrade into a more stable material. The half-life of Carbon-14 is 5,730 years. Choose ALL the true statements regarding the Carbon-14 isotope. A) 100 grams of C-14 decays to 25 grams in 11,460 years. B) The C-14 isotope is only useful for dating fossils up to about 50,000 years old. C) A sample contained 3,360 atoms of C-14. 8 half-lives passed and 210 C-14 atoms remained. D) If an ancient bone contains 6.25% of its original carbon, then the bone must be 22,920 years old. E) A sample of 4,000 radioactive C-14 atoms undergoes decay. After 5 half-lives there are 800 radioactive atoms remaining.