In the following passage some of the words have been left out. Read the passage carefully and select the correct answer for the given blank out of the four alternatives.

Racism is something we've all _______. Many people _______ to believe that race isn't a _______ category, but an artificial classification of people with no scientifically variable facts. In other words, the _______ we make between races has nothing to do with genetic characteristics. Race was created _______, primarily by how people _______ ideas and faces we are not quite used to. The definition of race all depends on where and when the word is being used. In U.S. history, the meaning of the label "white" has changed _______ time, eventually adding groups like the Italians, Irish and Jews. Other groups, mainly African, Latino, American Indian, Pacific Islander, and Asian descendants, have found the path for worldwide social _______ much more _______. The irregular border of ethnicities touch educational and economic opportunity, political representation, as well as income, health and social mobility of people of _______.