Name one of the air masses that can be found in north america (remember to use both the temperature and humidity descriptors and to spell it out completely, do not abbreviate). *

Actually, there are five types of Air Masses found in North America, namely :   a) Continental Arctic (cA),  b)  Maritime Polar (mP), c)  Maritime Tropical (mT), d)  Continental Tropical (cT), and e)  Continental Polar (cP).  Air masses are given a two-part name to describe the humidity and temperature of the region where they form. Example is : Maritime Polar (mP)  maritime air masses, are more humid, The second part of the name describes the temperature of the air mass, which depends on the latitude where it formed. The temperature is much colder when formed in polar areas.

I'm pretty sure it's c. extremely gradual but not 100% sure though.