Fact 1: Macroevolution occurs over geologic time above the level of the species.

Fact 2: Geologic time lines are expressed in geologic eras and periods.

Given the two facts above, answer the question "macroevolution occurs over what, above the level of the species?" with the following options: 
- atmosphere
 - years
 - growth
 - outer space
 - stress
 - Joules
 - humans
 - eras


 

        eras 