They are based on layers of rock the correspond to certain time periods, so my guess would be D.
Answer:
the action of measuring something.
Measurement is a comparison of an unknown quantity with a known fixed quantity of the same kind. The value obtained on measuring a quantity is called its magnitude. Magnitude of a quantity is expressed as numbers in its units.
1.8461 km/hr Well i need more characters so i might as well type a beautiful sentence for you to read and waste your time on.
Our bodies emit heat, and nerve endings in our skin can detect it.
Our eyes can detect visible light, but our bodies don't emit that.
