Geologic+Time+Scale

Do questions 1 through 5 __plus letters__ on textbook page 297. Then:
 * Use pictures and captions to tell about the geologic time scale.
 * Include details about the Precambrian, Paleozoic, Mesozoic, and Cenozoic Era.
 * Include dominant life forms.
 * Present the theories on how the Paleozoic and Mesozoic Eras ended.