Whatwas rhe monroe and why was it important

The information box says that the han added 4,000 miles of wall.refer to the mileage scale.how can this be true?

For most of the twentieth century, percentage of men had a college degree compared to women. however, if we focus on the data for americans born in or later, a higher percentage of women hold college degrees.

What were the shared risks of the signers of the declaration of independence were taking impending their names to the document?