Final answer:
English merchants used rum, which was made using molasses from sugar production, to buy slaves in Africa for the triangular trade system.
Step-by-step explanation:
The English merchants used rum to buy slaves in Africa as part of the triangular trade. This rum was made using molasses, which is a by-product of sugar production through the labor of enslaved people. English merchants also traded manufactured goods like cloth, guns, and ammunition for captives. The enslaved individuals then endured the brutal Middle Passage to be sold in the Americas, where they were forced to work on plantations producing items like sugar, which were in high demand in Europe and formed an essential part of this trade system.