Geologists have divided earth's history into time units, which are largely based on

a. oral histories.
b. fossils.
c. climates.
d. written correspondences.

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.

you will need these

an outline of all three paragraphsan identification of the historical era that you are writing aboutan explanation of the term mass productiona description of two ways new technology affected industrya conclusion that shows how new technologies allowed industrialization to grow