I dont know this one sorry
Explanation:
Public opinion is measured by election results, personal contacts, media reporting, and especially by polls. ... People express their opinions by voting, writing letters or emails, making phone calls or holding public meetings. Interest groups also share the views of their members in hopes of influencing public policy.
1. it stopped the spread of slavery north of the Ohio river
A person or group besides the two primarily involved in a situation, especially a dispute.
