Final answer:
The Border Ruffians were pro-slavery supporters from Missouri who used violent means to influence Kansas to become a slave state, in opposition to the anti-slavery settlers sent by northern states aiming to establish Kansas as a free-soil state.
Step-by-step explanation:
The Border Ruffians were pro-slavery activists who flooded Kansas with the intention of influencing the territory to become a slave state.
They engaged in acts of voter fraud and violence, a period known as Bleeding Kansas, and eventually were successful in drafting a pro-slavery constitution with the Lecompton Constitution.
In contrast, some northern states, including those who were influenced by the New England Emigrant Aid Society, sent settlers to Kansas hoping to make it an anti-slavery or free-soil state.
In nearby Missouri, which was one of the Border States, slavery was legally established, and neutrality in the conflict was impractical due to the state's resources and strategic importance, which made it a significant location for both the Union and the Confederacy during the Civil War.
In summary, the sentences should be completed as follows: The Border Ruffians were pro-slavery. Some northern states sent settlers to Kansas hoping to make it anti-slavery.
In nearby Missouri, slavery was legally established. In 1855, people from Missouri came to Kansas and voted to make it a pro-slavery state with the Lecompton Constitution.