Final answer:
The U.S. Constitution did not explicitly mention the word 'slavery', but it contained clauses that protected the institution of slavery, which were later addressed and rectified with the passing of the Thirteenth Amendment, which abolished slavery.
Step-by-step explanation:
The correct statement in regards to slavery in the Constitution is that the term 'slavery' is not explicitly written; however, the Constitution did contain clauses that protected the institution of slavery indirectly. Before the 13th Amendment, which abolished slavery, Article I allowed the importation of enslaved people to continue until 1808 without restriction and placed no limits on the domestic trade of enslaved people. Article IV included the fugitive slave clause that mandated states to return freedom seekers to the states where they were accused of escaping from. Moreover, the very structure of congressional representation, via the three-fifths compromise, accounted for slaves by allowing them to count as three-fifths of a person for determining representation.
The Thirteenth Amendment was a pivotal change to the Constitution, proposed in 1864, passed by the House in January 1865, and ratified in December of the same year, which permanently banned the institution of slavery across the United States, except as punishment for a crime. This amendment resolved the issue of slavery that had been left unaddressed by the original Constitution. It should be noted, the antislavery participants pointed to the Tenth Amendment and the due process clause of the Fifth Amendment to make arguments against slavery's constitutional legitimacy before the Thirteenth Amendment.
In summary, the Constitution, before its amendments, indirectly supported slavery through various clauses, although not explicitly using the term.