Imperialism is when a stronger nation takes control of a weaker nation. Nations do this for reasons like resources, power, prestige, or geopolitics.
Racism is the belief that one race is superior to another. This attitude was more common than not, and was one of the driving forces of why European took control of nations from native rulers, since they believed they were unfit to rule. This led to Social Darwinism, which is the belief that ANY ruler that isn't European is unfit to rule
The Berlin Conference was a conference held in 1884-85 to discuss the rules of division of Africa. It was agreed that any European country can take control of an African nations by notifying other European nations of its claim.
The Boer War was a war that started in 1867 and was a war between the Boers (farmers) and Britain, who fought over ownership of land in Africa. After many years of war, the British finally won, and the Boers integrated themselves in to the new British society in Africa.
Muhammad Ali led a reformation of Egypt. After his death, his grandson ismail, ismail created the Suez Canal, which although was a great invention and idea for Egypt's future, led them into massive debt and England had to take control of it to capatilize on Egypts mistake.
The Sepoy Mutiny began when soldiers were under the impression that England was using beef and pork fat to grease the cartridges of their guns. Hindu's don't eat beef because the cow is sacred to them, and Muslim's don't eat pork because they believe that the pig is unclean and shouldn't be consumed by the human body.