A(n) is a period unified by a common theme, often social or political.
a. era
b. period
c. decade
d. century

After world war 1 immigration was based on

After the success of the sputnik launch, the united states feared that they would never be able to launch their own satellite, the ussr had used technology developed by the united states, the soviets had superior nuclear capabilities, that any future us satellites would not be as successful.

What percentage of people in britain lived in cities in 1850? a.) less than 5% b.)between 6 and 10% c.) more than 20%