The process by which loans were preferentially given to white families in the mid-twentieth century, resulting in all white communities and school districts was called

During the mid-twentieth century, loans were preferentially given to white families resulting in all white school districts and communities. The process of denying loans primarily on the basis of race, sex or religion is called mortgage discrimination or mortgage lending discrimination. 

might be agreeing to participate ethically with other european nations in the slave trade

or notifying other european nations when taking possession   of african territories