Analyze this timeline illustrating one period of the modern era:
1848
1922
1949
1975
1991
1848: Karl Marx and Friedrich
Engels publish The Communist
Manifesto.
1922: The communist
Soviet Union is founded
by Russian revolutionaries.
1949: Chinese communists establish
the People's Republic of China.
1975: The Vietnam War ends with
a complete communist victory
1991: Communism ends in Russia
with the collapse of the Soviet Union
Which historical theme does the timeline most reflect?
A. Interactions between humans and the environment
B
The transformation of social structures
C The expansion and inter-action of political system
D culture of development and exchange