Answer D.
The next paragraph of the paragraph in the article has a version about ……..
A. what substances are part of all life.
B. how carbon-14 breaks down into nitrogen-14.
C. why does carbon-14 have such a long half-life.
D. other dating methods.
The next paragraph will have related content and follow the last paragraph of the article.
Translate the last paragraph: “Carbon dating cannot be effectively used in dating objects that are older than 80,000 years. When objects are that old, much of the carbon-14 has already decayed into nitrogen-14, and the molecule amount that is left doesn’t provide a reliable measurement of age. In the case of older objects, other age-dating methods are available, methods which use radioactive atoms with longer half- lives than carbon has”
The carbon dating method cannot be used effectively for artifacts over 80,000 years old. For artifacts of this age, most of the carbon-14 has completely decomposed to nitrogen-14, and the amount of molecules remaining is unreliable for age measurement. In the case of older artifacts, other dating methods are available, those using radioactive atoms with a longer half-life than carbon. For artifacts older than 80,000 years old carbon dating is no longer available, other methods are needed.