What are some examples when world history gives you the understanding of the world and how societies have impact on each other.

Answer 1

All of it! When new ideas are created in one society or culture, they often spread quickly, through trade or other means. Wars certainly force one group to have an impact on another. The spread of European diseases had a huge impact on Native American cultures and societies. The discovery of new foods, such as maize in the "new world," influence other societies. The examples go on and on and on.

Answer 2

Read this article:

http://www.apa.org/science/about/psa/2011/11/human-evolution.aspx