Which best supports the evidence that an asteroid collision may have caused caused the extinction of dinosaurs?
(1 point)
O Dinosaur fossil remains are found at the bottom of a body of water.
O Bodies of dinosaurs are only found in craters where asteroids collide.
O A Rare metal on Earth called Iridium is found in layers where dinosaurs disappeared.
O Many dinosaur skeletons are found in one particular rock layer.
The option that best supports the evidence that an asteroid collision may have caused the extinction of dinosaurs is:
- A rare metal on Earth called Iridium is found in layers where dinosaurs disappeared.
This is because Iridium is a rare element on Earth's surface but abundant in asteroids. The presence of a high concentration of iridium in layers associated with the extinction event suggests that it was likely caused by a significant impact from an asteroid or comet.
Which is correct about the fossil's location and age? (1 point)
O Fossils found in rock layers that have been disturbed are the oldest.
O Fossils found among numerous other fossils are most recent in age.
O Fossils found in lower rock layers are older than fossils found in upper layers.
O Fossils found in rock layers closest to the Earth's surface are the oldest.
The correct statement about the fossil's location and age is:
- Fossils found in lower rock layers are older than fossils found in upper layers.
This is because the principle of superposition states that in undisturbed rock layers, the older rocks are found at the bottom and the younger rocks are deposited on top. Therefore, fossils found in lower rock layers are typically older than those found in upper layers.
Why are time periods on the geologic time scale not even in length? (1 point)
They are based on a different type of calendar used to track Earth's history.
They are based on important events that happened in Earth's history.
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.
The correct answer is:
- They are based on important events that happened in Earth's history.
The divisions of time periods on the geologic time scale are based on significant geological events, such as the occurrence of mass extinctions or major shifts in Earth's climate. These events mark important changes in the Earth's history and are used as reference points for dividing the geologic time scale into different periods of varying lengths.