Question

Help with science!
Geologists divide Earth's long history into smaller units that make up the geologic time scale.
(a.) True
(b.) False

Where did scientists initially get info to develop the geologic time scale?
(a.) They collected and studied rock samples in Europe.
(b.) They studied rock layers and index fossils around the world.
(c.) They conducted research at libraries.
(d.) They didn't have any info; they just made an educated guess