Final answer:
Some Americans used social Darwinism to justify imperialism by asserting the superiority of certain groups and their duty to bring the benefits of western culture to other societies.
Step-by-step explanation:
Social Darwinism was used by some Americans to justify imperialism by claiming that certain groups of people were naturally superior and more likely to survive. They believed that their domination over other societies was not only their right but also their duty to bring the benefits of western culture and civilization. These ideas of social Darwinism supported the belief that the rich and powerful deserved their wealth and that the poor and weak were destined to be subjugated.