simple answer 6
Much of earth'swater was frozen into glaciers
What are two ways that's scientists can study earths climates history
epoch
Nitrogen
In sedimentary rock.
Historical geology.
History can not be measured it can only be recorded, studied or experienced.
precambrian era
to die
because
There are many more arthropods than other species but bacteria have the most species. Every new species of arthropods discovered have 10-12 new species of bacteria in them.
Astronomy This is the study of the earth and physical structure and history