1) The Appalachian Mountains, running along the eastern coast of the United States, are one of the oldest mountain ranges in the world.

2) The concept of proportional representation, used in some electoral systems, aims to ensure that political parties' representation in government aligns more closely with the proportion of votes they receive from the electorate.

3) The word "table" contains two vowels: A and E.

4) The most-watched television event in the United States is the Super Bowl, with millions of viewers tuning in each year.