52
Lesson 52 of 84 · Westward Expansion
Farming Technology on the Frontier
World War I (1914–1918) was one of the deadliest conflicts of its time. New weapons — machine guns, tanks, and poison gas — caused devastating casualties across Europe.
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.
Check Your Understanding
Question 1
1 of 2What tool puts events in order?