How are eras and periods of the geologic time scale named? a) they are named for the places where geologists first described rocks or fossils from that time. b) their names are based on the names of scientists who discovered the rocks and fossils. c) they are named after plants and animals that lived during that time. d) their names are based on the number of centuries within that length of time.

A) They are named for the places where geologists first described rocks or fossils from that time

Explanation:

The relationship between  plant and animals, layers and types of rocks, fossils and radioactive dating are used for preparing Geologic Time Scale. Geologic time is comprise of  four  Eons namely Hadean (the initial stage) followed by Archean and Proterozoic and Phanerozoic in the recent . The Eons are classified into eras and theses eras reflect the changes in fossil record.  Eras are further divided into periods  and some periods into Epochs.

In periods a single rock system is found while the division in the era's reflect major changes in fossil record.

a. They are named for the places where geologists first described rocks or fossils from that time.

Explanation:

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the answer is b. hope this .