1. Explain what might happen if one was to go back in time to the lower Precambrian and prevent photosynthesis from evolving? Please offer specifics

2. There is a lot of empty space on the timeline. Generally speaking, what is happening during these empty spaces? Please offer specifics.

3. Using data from your timeline, comment on this statement: “A long time ago humans had to fight off marauding dinosaurs.”

4. If humanity finds an Earth-like planet around a Sun-like star, which is 10⁹ years old, should we expect to find intelligent life? Why or why not? Be specific.