Option c. dendrochronology
tree rings or dendrochronology they allow to use it in calibration for carbon-14 on temporal placements of fragments of wood (from long dead trees).
Example Bristle cone pines (1957) 4723 years old
The half-life of radium-226 is 1600 years. How many grams of a 0.25 g sample will remain after 4800 years?
this would be 0.03125 gram
207 is the mass number. 82 would be the atomic number
Answer:

Explanation:
The equation for density is:

We plug in the given values:

