Fill in the missing letters in the paragraph.
The number of underlines shows how many letters you need to fill in. You may answer with the full word or only the missing part.
---

Organic mate_ _ _ _ _ such as wood, bone, and plant fibers contain a small am_ _ _ _ of radioactive carbon. After a living org_ _ _ _ _ dies, this carbon begins _ _ decay at a steady rate. By measuring how much of it rem_ _ _ _ , researchers can est_ _ _ _ _ how long ago the material was formed. This tech_ _ _ _ _ allows archaeologists to place artifacts and human remains within a chrono_  _ _ _ _ _ _ framework, even when no written records ex_ _ _ .