Front

What is the primary purpose of the geologic time scale?

Back

To organize Earth's history chronologically

Front

How old is Earth according to scientific evidence?

Back

4.6 billion years old

Front

What type of rock layers provide the best evidence for studying Earth's history?

Back

Sedimentary rock strata

Front

What principle states that younger rock layers are typically found above older layers?

Back

Principle of superposition

Front

Order of geological eras from oldest to newest?

Back

Paleozoic, Mesozoic, Cenozoic

Front

What can scientists learn from studying rock strata?

Back

Past climate conditions and life forms

Front

Which dating method is used to determine the absolute age of rocks?

Back

Radiometric dating

Front

What is an unconformity in rock strata?

Back

A gap in the rock record

Front

How do index fossils help scientists study rock strata?

Back

They indicate the relative age of rock layers

Front

What is the name for the longest division of geological time?

Back

Eon