1. What observations would you need to make to determine whether the Moho was greater than or less than the average depth of 35 km where you live?

2. What physical features can you identify where you live that were formed under the principle of uniformitarianism?

3. In Figure 11.8B, how do we know whether lava or the road it covers is older? Refer to absolute ages and relative ages in your answer.

4. New evidence shows that most stars have orbiting planets and that planets are more common than stars. Do you think that there might be life on other planets besides Earth? What conditions would be necessary to support life? How, if at all, would the discovery of life on another planet change your perspective on Earth’s life?