The Behavioral Science Unit (BSU) is a part of what agency?

Federal Bureau of Investigation (FBI)

Social Darwinists embraced laissez-faire capitalism and racism because they tend to believed that government should not interfere in the "survival of the fittest" by helping the poor and thereby promoted the idea that some races are biologically superior to others.

Explanation:

Social Darwinism can be defined as the way in which scholars use to describe the practice of misapplying the biological evolutionary language of Charles Darwin to politics, the economy as well as the society.

The ideas of Social Darwinism pervaded many aspects of American society in the Gilded Age, including policies that affected immigration, imperialism, and public health because Many Social Darwinists embraced laissez-faire capitalism and racism and they tend to believed that government should not interfere in the "survival of the fittest" by helping the poor which in turn promoted the idea that some races are biologically superior to others which is why the ideas of Social Darwinism pervaded many aspects of American society in the Gilded Age, including policies that affected immigration, imperialism as well as the public health.