Many progressive supporters of immigration restrictions justified their views by appealing to , a field that involved grading ethnic groups according to their alleged genetic qualities.

Eugenics

Explanation:

Eugenics is the belief that the human race should be improved genetically by selective interbreeding. It is a belief that is closely related to racism because eugenics tend to equate "races" with desirable or undesirable genetic characteristics.

Eugenics was very popular at the end of the nineteenth century, and at the turn of the twentieth century, even among the progressives. Many of them supported the acts that restricted immigration to Northern European Countries.

disorders of the brain include both behavior disorders and other psychiatric illnesses. the primary difference between a behavior disorder and another type of psychiatric disorder is the presence of choice. psychiatric conditions are considered to be involuntary while in behavior disorders, choices are essential.

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