Why are time periods in the geologic time scale are not even in length?
Responses
They are based on the thickness of the Earth's rock layers.
They are based on the thickness of the Earth's rock layers.
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 important events happened in Earth’s history.
They are based on important events happened in Earth’s history.
The correct response is:
They are based on important events that have occurred in Earth's history.
The time periods in the geologic time scale are not even in length because they are based on important events that have taken place in Earth's history. These events, such as mass extinctions, major geological or climate changes, or the origins of significant groups of organisms, serve as markers that help scientists divide Earth's history into distinct time intervals. The boundaries between these time periods are often defined by changes in the fossil record or other geological evidence. Therefore, the length of each time period is determined by the duration of the events and processes that occurred during that time, rather than a fixed unit of measurement.