What else should the second group of reserchars measures to test its hypothesis

facts: the 14th amendment

the 14th amendment addresses citizenship rights and equal protection of the laws.

the 14th amendment was intended to protect the rights of former slaves after the american civil war.

the 14th amendment was approved by congress in june of 1866 and ratified by the states on july 9, 1868.

the 14th amendment establishes that all persons born in the united states are citizens and are guaranteed all the rights of citizenship.

the 14th amendment establishes that the law protects all citizens equally.

in this case the passage of the 14th amendment   that was violated was the last part in which it states that there is equal protection of the law.

explanation:

with the profits from the european sales, merchants purchased europe's manufactured  goods, including tools and weapons. then the merchants shipped those manufactured  goods, along with the  american  sugar and rum, to west africa where they were bartered for  slaves.