Final answer:
Guaranteeing the welfare of the poor and unemployed by the federal government came later than the other functions, such as promoting industrial growth by tariffs, regulating trusts, and immigration policies.
Step-by-step explanation:
Among the listed functions of the federal government in the context of United States history, guaranteeing the welfare of the poor and unemployed came later than the other functions mentioned. The early industrialization of the United States prompted the creation of protective tariffs to promote industrial growth and the regulation of monopolistic trusts, as seen in the Sherman and Clayton Acts. Immigration has been a subject of federal regulation since the late 19th century.
However, the federal government directly intervening to ensure the welfare of citizens, through programs such as Social Security and federal unemployment insurance, were largely a result of the New Deal policies of the 1930s during the Great Depression. These welfare programs marked a significant expansion in the role of the federal government with respect to direct economic support for individuals.