Travel on America's rivers increased after which year?

Ineed with number 17 i don’t get it at alll

Which idea is central to democracy in the united states? everyone has an equal right to consumer goods. people should not compromise to settle differences. the minority has authority over the majority. freedom must be balanced with respect for the law.

Arecent poll of 500 residents in a large town found that only 36% were in favor of a proposed referendum to build a new high school. find the margin of error for this poll if we want 95% confidence in our estimate of the percentage of residents in favor of this proposed referendum.