Final answer:
Citizenship was expanded to Black people through the passage of the Fourteenth Amendment to the U.S. Constitution, granting them citizenship and equal protection under the law.
Step-by-step explanation:
Citizenship was expanded to Black people through the passage of the Fourteenth Amendment to the U.S. Constitution. This amendment, which was passed by Congress in 1866 and ratified in 1868, granted citizenship to all persons born or naturalized in the United States, including formerly enslaved Black people. It also prohibited states from denying equal protection under the law to any person within their jurisdiction.
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