Answer:
The Earth also gives us clues about the levels of greenhouse gases that existed in the past. For example, ancient air bubbles trapped deep in the ice of Greenland and Antarctica reveal how much carbon dioxide was present long ago.
Explanation:I learn it in 8 grade.
C.) Geography plays a role in historic events.
I would say that you have to look up this answer or ask another person because this is tricky
A, in urban areas :)
Urban areas have bigger populations than rural ones and the Rocky Mountains have terrain that is difficult to settle on
