Archaeologists and historians agree on the exact date that human arrived in the Western Hemisphere.

That statement is false.

Explanation:

The time when humans first arrived in western hemisphere occurred far before humans understand the concept of numbers and writings.  Since there's no physical evidence to rely on, it is impossible for Archeologists and Historians to determine an exact date.

In the end, all they can do is predict the time period.

Based on the estimation of how old the artifacts / architectures that they found. they predicted that human arrived in western hemisphere around  29,000 to 57,000 years ago.

im not sure its either a leader of a group of congresspeople or a person from a congressmans district

sorry im not sure