1.human evolution
2.dinosaurs extinction
3.creation of the ocean
2.how many eras, eons (periods or epochs) are there? 4 eras, 6 eons, and 16 periods.
3.what do you think are the differences between eras and eons? I think that eras are like the titles and the eons the subtitles.
4.why did scientist create eras and eons in the first place? Because its more easy to them to name the eras and the eons then the year that was the event.
