Social structure is a complex topic and involves and revolves around the basic frameworks we usually use to describe the common ways how people bond into hierarchically structured organizations, with these being either formal or informal.
Artifacts are things that were made by our ancestors they are important BC without them you will never have stuff like wheels ,cars and stuff like that
Explanation:
Its because of humans cause they are evil
as an empire on top of mountains so no intruders could get in.
Due to the external atmospheric pressure. Initially the pressure inside the can is balanced by the atmospheric pressure. But as the air is removed from inside, the external pressure dominates.