Answer:
Imperialism is a political doctrine according to which certain country politically and economically holds some other country, usually under an excuse that they will civilize them.
Step-by-step explanation:
African continent in 19th Century was totally under the control of European countries. Under the pretense that they are trying to economically develop whole continent they started controlling them. They tried to control them in many different ways.
Probably the most infamous regime was established in Belgian Congo. Not only that economically Leopold II devastated the country, but during that period between 5 and 8 million people died.
Imperialism of this period was supported with the theory of social Darwinism.