Use the drop-down menus and what you have learned about potassium-argon dating to complete the sentences.
Radioactive dating can be compared to an hourglass, with the
✔ unstable
elements on the top.
Scientists compare
✔ parent and daughter elements
in the rock to determine its age.
Potassium-argon dating is ideal for dating
✔ igneous
and
✔ ancient
rock.