Question - According to the website, why is the history of black Americans and their strife for civil rights significant to the history of the United States?

According to the website, why is the history of black Americans and their strife for civil rights significant to the history of the United States?

Answer: 

Because it was symbolic of the fight for rights for all people. As well, such movements have not only secured citizenship rights for blacks but have also redefined prevailing conceptions of the nature of civil rights and the role of government in protecting these rights.