The geological timescale was first developed using the fossil record, but this provided only a system of relative dating; absolute dates weren't established until the discovery of:
A)radioactive decay.
B)isotopes.
C)sedimentary rocks.
D)fossil series.

Question

Quizplus · Accepted Answer

Radioactive decay allows for the determination of absolute dates, which are necessary for accurately placing events on the geological timescale. Isotopes are involved in radioactive decay, but their discovery alone did not establish absolute dates. Sedimentary rocks and fossil series were important in developing the relative dating system, but also didn't establish absolute dates.

The Geological Timescale Was First Developed Using the Fossil Record