which statement explains why ammonites are a good example of an index fossil?
A. Ammonites existed only in oceans.
B. Ammonites existed long before the dinosaurs.
C. Ammonites existed in a small geographic area.
D. Ammonites existed for a relatively limited period of time.
D. Ammonites existed for a relatively limited period of time.
what is the theory that describes the movement of landmasses on Earth's surface?
A. divergence
B. subduction
C. plate tectonics
D. continental drift
D. continental drift
how does the fern Glossopteris provide evidence for the movement of the continents?
A. it existed in the Permian period.
B. it is the oldest plant on Earth.
C. it lived at the same time as Lystrosaurus.
D. it was found on many continents.
D. it was found on many continents.
D. Ammonites existed for a relatively limited period of time.
The correct answer is D. Ammonites existed for a relatively limited period of time. Explanation:
Index fossils are fossils that are used to help determine the age of the rock layers in which they are found. They are typically organisms that lived for a short period of time and were geographically widespread.
To understand why ammonites are a good example of an index fossil, we need to consider the characteristics of index fossils. Index fossils are useful because they are easily recognizable, abundant, and have a known age range. In the case of ammonites, they are excellent index fossils because they fulfill these criteria.
Ammonites were marine creatures that lived around 240 to 65 million years ago during the Mesozoic Era. They were present on Earth for a relatively limited period of time, spanning several geological eras, making them useful for dating rocks from that time period.
Ammonites were also widespread, inhabiting various regions of the oceans and different environments, such as shallow seas or deep waters. This broad distribution helps in correlating the age of different rock layers across different geographic locations.
On the other hand, options A, B, and C are not accurate explanations for why ammonites are good index fossils. While ammonites did exist only in oceans (option A), this fact alone does not make them an ideal index fossil. Similarly, while ammonites did exist long before the dinosaurs (option B), this does not inherently make them good index fossils either. Finally, ammonites did have a geographic distribution (option C), but they were not limited to a small area, but rather spread across a large geographical range.