It meant easier and cheaper access to goods within the treaty's members. This in turn promoted increased economic interdependence.
For example, before the treaty was signed, many auto-parts were manufactured and assembled in the United States. After NAFTA, it became cheaper to just outsource the manufacturing of these parts or the vehicle assembly altogether, as import/export taxes subsided or were completely eliminated.
Hello and Aló in Canada; Hola in Mexico.
Canada and Mexico do not border each other
Mexico is warmer as it is much closer to the equator than Canada.
Canada is larger than both the US and Mexico.
Mexico is to the south of Canada.
As direct economic help? Canada does not provide such foreign aid to Mexico.
Economic interdependence, common goals, history and demography is the answer. 10% of the American population can trace their origins to Mexico, so having a wealthy Mexico increases the chances of having a powerful ally next door. Just for you to ponder, if Mexico became a fairly industrialized country on par to beaten Greece or Portugal, it would be the 7th largest economy in the world, just behind Germany and Japan.
The Economic Boom Has changed them
To increase international trade.
Economic growth and security
economic growth and security
It united Mexico and Canada in economic opposition to the United States.
Integrated, as a single economic block.
Not really; Canada is an important trade and business partner of Mexico, but the Canadian government hasn't made any serious effort to help Mexico solve its economic and social problems. Canada has however, promoted economic integration, as part of the North American Free Trade Agreement; it includes transport and financial agreements, as well as increased foreign direct investment (USD 1.75 billion throughout 2012) towards Mexico.
It was to encourage the economic activities between the United States, Mexico, and Canada.
Canada and Mexico
They don't really "help" each other. The three countries are important trade an business partners, and depending on the bilateral relationship, (US-Mexico, Canada-Mexico, Canada-US) it also includes security, diplomatic and defense treaties that allow for increased economic integration.