D. It provided a racial justification for conquering nonwhite people.
Social Darwinism was a theory that applied the principles of biological evolution to social, political, and economic issues. According to this theory, certain races and nations were deemed superior to others, and were therefore justified in their efforts to dominate and exploit these supposedly “inferior” races and nations. This theory had a significant impact on new Imperialism, as it provided a justification for European nations to expand their empires and conquer non-white people. The idea was to “civilize” the less-advanced societies, but it was often used as an excuse for exploitation and subjugation.