Choose the right order according to the passage.
1. These happen because of disturbances far below the surface of the earth.
2. We know the most about the earth`s outer skin because that is where we live.
3. For thousands of years people have wondered what is inside the earth.
4. It is also where events occur, such as earthquakes and volcanic eruptions.
5. Only recently has it been possible to get some idea of what the earth might look like inside.