Question

Geologists have divided Earth's history into time units, which are largely based on _________.

A. oral histories.
B. fossils.
C. climates.
D. written correspondences.

Answer 1

Geologists use fossils to divide the world's history into eras and periods. Fossils of organisms, plants and animals are old traces that can be used to determine the era which it belongs. Its age is determined through the conventional method: carbon dating.

Answer 2

Geologists have divided Earth's history into time units, which are largely based on fossils.

Fossils are the preserved remains or traces of animals, plants, and other organisms from the remote past.

The correct answer between all the choices given is the second choice or letter B. I am hoping that this answer has satisfied your query and it will be able to help you in your endeavor, and if you would like, feel free to ask another question.