Which air masses have the greatest effect on weather conditions in much of the united states?

Continental polar and maritime tropical.

Explanation:

As these surface air mass are marked by high pressures and have cold temperatures, and the maritime air masses are cool, moist and unstable. Found along with the North American state. The continental is characterized by the dry winds, and the polar is hot air near the surface and the tropical air mass is warm and the arctic is extremely cold.

Answer the above statement is correct (true);

Answerland;