Why are time periods on the geologic time scale not even in length?(1 point)

Question

Responses

They are based on important events that happened in Earth’s history.
They are based on important events that happened in Earth’s history.

They are based on a different type of calendar used to track Earth’s history.
They are based on a different type of calendar used to track Earth’s history.

They are based on the type of fossils found in rock layers of the Earth.
They are based on the type of fossils found in rock layers of the Earth.

They are based on the thickness of the Earth's rock layers.
They are based on the thickness of the Earth's rock layers.

Answer 1

The correct response is:

They are based on important events that happened in Earth’s history.

The time periods on the geologic time scale are defined by significant geological and biological events, such as mass extinctions or the emergence of notable life forms, rather than being of uniform length.