Why are core samples considered a form of *direct* evidence about Earth's structure?

They generate seismic waves that can be read by sensors around the world.

They allow scientists to physically hold and test the materials that make up Earth's layers.

They provide a complete and unbroken record of Earth's entire history from a single location.

They are the only way to measure the exact temperature of the Earth's mantle.

A research vessel uses a large drill over an oceanic trench. What is the most probable goal of this operation?

To measure the water's salinity and temperature.

To extract rock from beneath the seabed for study.

To map the topography of the ocean floor using sonar.

To install sensors for detecting underwater volcanic activity.

The outer layer is a uniform liquid ocean of molten magma.

The outer layer is composed of different types of solid rock.

The outer layer is a hollow space containing vast underground caves.

The outer layer is primarily made of ice and frozen gases.

It measures the speed of seismic waves through different materials.

It provides physical proof of the rock types predicted by the models.

It generates a complete magnetic history of the Earth from a single sample.

It predicts future volcanic activity based on mineral content.