Explain how business leaders of the gilded age used the concept of “socail darwinism” to support their business tactics?

Social Darwinism is the belief that people and business are subject to the same laws of nature and natural selection. This has been used by business leaders, both in the Gilded Age and today, to create a belief that the strongest businesses are the ones that survive because they survive the competitive process of natural selection.

So, massive oil companies and railroad companies (and tech companies and banks today) used social darwinism to explain their rise to almost monopoly status as a "natural" thing that was accomplished merely using the laws of nature.

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.