The north american free trade agreement (nafta) unites the united states with in one of the world's largest free-trade zones.

Canada and Mexico

Explanation:

NAFTA was signed by US, Mexican and American presidents in 1993 and it  came into effect in January 1994, It created a trilateral trade bloc.

There are three members states of NAFTA, Canada, US and Mexico.

It was created to eliminate the barriers to investment and trade between US, Mexico and Canada. It eliminated tariffs on more than one half of Mexico's exports to US and more than one-third of US exports to Mexico.

It boosted US economic growth by 0.5% a year, agriculture, automobiles and services benefited the most. The export of US farm products to Mexico and Canada also quadrupled from 1993 to 2016.

if you could provide the poem below, i'd be happy to you!

explanation:

you didn't give us the poem, or the title of the poem. but it is essential for you to give us that, otherwise we can not detect when the poem has a tonal shift!

d. the great plains       hop3 this yo