Given the task definition and input, reply with output. In this task, you are given a sentence and question which can be answered using the sentence. Your task is to answer the question using the information from the sentence. The answer to the question is unique and it is a continuous text span from the sentence.

Sentence: The album is named after the discredited pseudoscience of phrenology , the study of head shapes to determine intelligence and character , which was used to rationalize racism during the 19th century in the United States . 
 Question: what was something used  to do?

rationalize racism during the 19th century in the United States .