The division of earth’s history into smaller units makes up the
a.
eras
c.
periods
b.
geologic time scale
d.
sequence of events

The division of Earth’s history into smaller units makes up the geological time scale.

Further Explanation:

Geology is a scientific study of the history, structure, and origin of the earth. The geological time scale mainly divides geological earth history into different intervals of the time that is defined by changes on earth or major events. The largest division of geological time is an eon. The smaller units of eons are referred to as eras.4.6 billion year antiquity of the earth is characterized into four eons,

Proterozoic eons, Archean and Hadean eons together are referred to as Precambrian time. This time constitutes a majorly ninety percent history of the earth. The division of the geological time scale mainly depends upon the events occurring in the geological history of the earth. But there are some divisions of geological time scale that entirely depends upon the fossil records.

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Answer Details:

Grade: High School

Subject: Biology

Topic: Ecology

Keywords:

Geological, time, scale, Precambrian time, events, entirely, fossils record, earth, history, eons, Archean, Hadean, intervals, Proterozoic.

gold i'm pretty sure i might be wrong