discussions among earth scientists about new data scientific books defining the layers of Earth a lead scientist explaining the structure of Earth a physical model of Earth showing its layers
Some scientists once believed that Earth was solid like a marble. Which of these has been most responsible for changes in the scientific view of the structure of Earth?

Options:
- discussions among earth scientists about new data
- scientific books defining the layers of Earth
- a lead scientist explaining the structure of Earth
- a physical model of Earth showing its layers

discussions among earth scientists about new data