Explain the concepts of racism and social darwinism and how they relate to the policy of imperialism

Racism, social darwinism and imperialism are very much intertwined, since social darwinists believe that Darwin's assertion that nature is determined by the "survival of the fittest" means that those who are more "advanced" are "allowed" to dominate and kill those who are less advanced. This leads to people like white Europeans invading places like Africa, where the majority of people are black, under the idea that they are inferior, which is, of course, racist.