Which statement correctly contrasts relative dating with radiometric dating?

• A. Relative dating yields an approximate age based on rock layer sequence
• B. Relative dating uses layer position to determine order; radiometric dating provides actual ages using isotopes
• C. Radiometric dating determines order of layers
• D. Relative dating uses DNA divergence to estimate age

Answer: (B)

Understanding how scientists estimate the age of rocks involves two complementary ideas: order versus actual time. Relative dating looks at the arrangement of rock layers and fossils to determine which events happened first, telling us which rocks are older or younger in a sequence. It does not give a specific number of years.

Radiometric dating inserts the actual time element. By measuring the amounts of radioactive parent isotopes and their stable daughter products in a mineral, and knowing how quickly they decay, scientists calculate an exact age in years.

So the statement that best contrasts the two is that relative dating uses layer position to determine order, while radiometric dating provides actual ages using isotopes. The other options mix up what each method measures or suggests methods (like DNA) that aren’t used for dating rocks in this context.