Astream has an interwoven network of small channels separated by much loose debris.

the precambrian aged rocks could be found in australia. australia is a region that has a lot of ancient civilization history from million years ago. in this region, there are a lot of recognizable fossils buried in its land which is considered a precambrian-aged rocks

i'm sure the answer you are looking for would be

a. an ice age

hope this contact me if this didn't or you need with more answers : )