Your group is asked to develop a method for reconstructing the sequence and approximate numerical ages of several rock layers. Which investigation plan would best combine relative and absolute dating?

Scientists create models to explain structures that cannot be observed directly. Which method provides the most reliable model of Earth’s interior?

Researchers discover well-dated fossils showing that a group of organisms appeared earlier than indicated on the current geologic time scale. What is the most scientifically sound   response?

A fossil lived for millions of years and was found in only one area. Is it a good index fossil?

Scientist A uses rock layers, while Scientist B uses rock layers and radiometric dating. Which approach gives more information about age?

A student says that an index fossil gives the exact age of a rock. Which statement BEST evaluates the student's claim?

Seismic waves change speed and direction at several depths. What does the presence of these changes suggest about Earth’s interior? Earth                    .

-waves disappear beyond approximately 103°, while P-waves reappear beyond their shadow zone. What can scientists infer from this pattern?

Non-avian dinosaurs disappeared near the end of the Cretaceous Period, while mammals later became more diverse. Which explanation best connects these events?

Layer X contains fossils of the first fish with jaws, while Layer Y contains fossils of the first reptiles. What can be concluded from this evidence?

A sequence of undisturbed rock layers is labeled from bottom to top as A, B, C, and D, while a fault cuts through layers A, B, and C but does not cut layer D. Which interpretation BEST explains the relative ages of these features?

A scientist needs to determine the age of a very old rock estimated to be millions or billions of years old. Which evidence and technique would provide the most appropriate information?

Scientists discover the same index fossil in Rock Layers A, B, and C, but the layers are in different areas. What does this pattern most strongly suggest? The              .

Scientists compare seismic records from stations around the world. How would you explain the absence of direct P-waves at a station located 120° from an earthquake’s epicenter? It __________.

The instrument detects P-waves but no S-waves along a particular path. Apply your knowledge on seismic waves, what type of material can be found along this path?

A rock layer contains evidence of large coal swamps and fossils of some of the earliest reptiles. Using the Geologic Time Scale, during which period did these organisms live?

A museum exhibit must present the development of life in the correct historical order. Which sequence should the museum use to recount the history of life from the oldest event to the most recent?

A paleontologist discovers fossils of the earliest flowering plants together with fossils of non-avian dinosaurs. In which geologic period should the paleontologist most likely classify the rock layer?

Scientists find an index fossil in Rock Layer A and the same index fossil in Rock Layer several kilometers away. How could the scientists use this evidence? To              .

S-waves are detected only in certain regions after an earthquake. Why are S-waves not detected on the opposite side of Earth from an earthquake? S-waves _____________.

Geologists use the geologic time scale as a record of Earth’s major changes. Why is the geologic time scale useful in recounting Earth’s history? It _______________.

A scientist examines two undisturbed rock layers and observes that one layer is below the other. Which conclusion correctly applies the Principle of Superposition?

Seismic waves travel through Earth after an earthquake. Which type of seismic wave can travel through solids, liquids, and gases?

The geologic time scale organizes Earth’s long history into several divisions. What is the largest division of geologic time?

Fossils provide evidence that helps scientists study the history of Earth and determine the relative age of rocks. Which method uses fossils to compare the ages of rock layers from different locations?

Fossils provide evidence that helps scientists study the history of Earth and determine the relative age of rocks. Which method uses fossils to compare the ages of rock layers from different locations?