How does change lead to positive and negative effects in society

Change may be positive and negative. For example, negative change may seem all rotten but a lot of the time there are wonderful things in it. To begin with, getting sick is negative but it is also positive. When people get sick it's negative because they can not go anywhere they want to go.

i belive the classic sword and a shield would do

these civilizations were located around fertile rivers, where they could produce an abundance of crops