1) How do chlorofluorocarbons degrade ozone (write out reaction)? Describe how this degradation leads to negative consequences for organisms on Earth.
2) Describe how geologists assess relative and absolute time. Be sure to mention all of the principles related to relative timing and provide a brief description of each.
3) Describe how the emergence of organism with hard partsaided our ability to characterize and identify evolutionary trends in Earth history. When did hard parts first appear and in what organisms?