Answer :
Social Darwinism is the belief that some people or groups are superior and others are inferior. It is believed to be part of the natural order and therefore those being more advanced are superior and that leads to racism.
Believing that some peoples are inferior and others superior creating racist thinking makes it easier to take them over and justify the imperialism. More technologically advanced countries took over less modern countries or regions believing they were bettering the civilization by bringing western thinking and technology. They outlawed native religious practices and social norms while supporting western culture. This thinking also convinced the conquering power that they were more suited to be in control of natural resources and economic trade again justifying their behavior in taking over the economic controls in a country or region. This gave the imperial power more control and power while decreasing the power of the conquered land.