Why are time periods on the geologic time scale not even in length?(1 point)
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 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.
Skip to navigation
page 16 of 16
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 correct answer is: They are based on important events that happened in Earth's history.
Explanation: The time periods on the geologic time scale are not even in length because they are based on significant events that occurred in Earth's history, such as mass extinctions, the formation of major mountain ranges, or the appearance of new groups of organisms. These events do not happen at regular intervals, so the time periods on the geologic time scale vary in length. For example, the Jurassic Period, known for the dominance of dinosaurs, lasted about 56 million years, while the Cretaceous Period, when the dinosaurs went extinct, lasted approximately 79 million years. So, the variation in the length of the time periods reflects the geological and biological changes that took place during Earth's history.