Answer:
Radioactive isotopes are unstable and will decay. ... The isotopes will decay into a stable isotope over time. Scientists can tell how old the rock was from looking at the radioactive isotope's half-life, which tells them how long it would take for there to be half the radioactive isotope and half the stable isotope.
C. The area of the US doubled
Answer: B
Explanation: Good luck! :D
<em>Dublin, Ireland is the Largest city in it's country or region. I'm Irish, so this really hit close to home.</em>
You’ll have to give a little bit more context for me to answer.
