The two correct answers you could determine by reading the geologic time scale are:
- the number of eras in Earth's history
- the events that ended major divisions of geologic time
The geologic time scale provides an overview of the different divisions of time (eras, periods, epochs) and often includes significant events that mark the transitions between these divisions. While it gives information about the types of life forms that existed during certain periods, it does not provide explicit details on every life form that lived in each era.