Final answer:
Supporters of the Free-Soil Party included abolitionists, those who believed slavery was detrimental to white workers, and small farmers, all of whom opposed the expansion of slavery into the West.
Step-by-step explanation:
The supporters of the Free-Soil Party were those who believed that the westward expansion of slavery would negatively impact white workers, as it would force them to compete with slave labor. Specifically, this group included abolitionists, individuals concerned about the effects of slavery on white workers, and small farmers who were interested in preserving the territories in the West for free labor. The Free Soil movement was in direct opposition to slaveholders and those who favored the expansion of slavery into new territories, as it aimed to prevent the spread of slavery and protect the interests of free men seeking opportunities in the westward expansion.