In Azoic era, there were no people, no plants, no animals. That's why this this era was also called as ....

In the end of Azoic era, the Earth began to cool because ...

What is the second era of prehistoric time line?

There was very heavy raining down everyday in the early of Proterozoic era. The water filled the holes in the surface of Earth that made ...

Long long time after there was ocean in the Earth, there was a tiny living thing in the ocean that was called .....

The bacteria evolved or change to make oxygen in the ocean. It made the ocean turned into ....

Bacteria as the first living thing were found in the Proterozoic era. So, this era was also called ...

Long long time after bacteria lived in the ocean, there were also other animals that lived in Proterozoic era EXCEPT ....

There were only ONE land in the Proterozoic era. It was called ....