Answer:
Eugenics
Step-by-step 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.