Why are time periods on the geologic time scale not even in length?(1 point)
Responses
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 that happened in Earth’s history.
They are based on important events that happened in Earth’s history.
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 important events that happened in Earth’s history.
The correct response is: They are based on important events that happened in Earth's history.
The time periods in the geologic time scale are not even in length because they are based on significant events that took place in Earth's history, such as mass extinctions or major geological shifts. These events do not occur at regular intervals of time, so the divisions in the geologic time scale reflect the occurrence and importance of these events rather than equal time intervals. For example, the 66-million-year interval known as the Cretaceous-Paleogene boundary marks the extinction event that wiped out the dinosaurs, while the 251-million-year interval between the Permian and Triassic periods marks the largest mass extinction in Earth's history. Therefore, the unequal length of time periods allows for a more accurate representation of Earth's complex history.