NAFTA was important to North America countries because it

It was an agreement signed by Canada, Mexico, and the United States, creating a trilateral trade bloc in North America.

Explanation:

places of higher salinity. there are parts of the ocean where hardly any rain falls but warm dry winds cause lots of evaporation. this evaporation removes water – when water vapour rises into the atmosphere, it leaves the salt behind, so the salinity of the seawater increases. this causes the seawater to become denser.