50
Lesson 50 of 84 · U.S. History
World War I and America
The Industrial Revolution changed manufacturing. Factories replaced workshops, machines replaced hand tools, and cities grew rapidly as people moved from farms to find jobs.
Key Facts
1
Timelines show events in order.
2
Cause and effect explain why things happen.
3
Oral histories preserve community stories.
Check Your Understanding
Question 1
1 of 2Which is a secondary source?