Question

What is the largest time unit in the geologic time scale?

Answer 1

The geologic history of the Earth is broken up into hierarchical chunks of time. From largestto smallest, this hierarchy includes eons, eras, periods, epochs, and ages. All of these are displayed in the portion of the geologic time scale 

Answer 2

The Geologic time scale ( GTS ) has numerous numbers and scales also from largest to smallest and the largest time scale is the Supereon composed of eons , eons which are divided into era's which are in time divided into periods , epochs , and ages.

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