Atreaty was signed in 1842 to end the border

Yes, this was called the Webster-Ashburton Treaty. The Webster–Ashburton Treaty, signed August 9, 1842, was a treaty that resolved several border issues between the United States and the British North American colonies (the region that became Canada).

a. because the u.s. was the leading with the most technology, economy, etc. also was teamed with other allies witch boosted the economy and materials to improve technology and use it.