37
Lesson 37 of 84 · History
Primary and Secondary Sources
Ancient Mesopotamia, between the Tigris and Euphrates rivers, is called the cradle of civilization. The Sumerians invented writing, the wheel, and early forms of government around 3500 BCE.
Key Facts
1
Cause and effect explain why things happen.
2
Oral histories preserve community stories.
3
Primary sources come from the time of the event.
Timeline
1929
The Great Depression begins
1941
The U.S. enters World War II
1945
World War II ends
Check Your Understanding
Question 1
1 of 2What tool puts events in order?