Question

what causes air masses to move? when prevailing westerlies shift directions and move toward the west. weather conditions change rapidly to produce storms. a collision takes place between two natural wind patterns. long, narrow bands of wind blow in the upper atmosphere.

Explanation:

Jet streams are long, narrow bands of strong wind in the upper atmosphere. They play a crucial role in moving air masses. Prevailing westerlies are a general wind pattern but their shift direction as described is not the main cause. Weather conditions changing to produce storms is a result of air - mass movement in some cases, not the cause. A collision of two natural wind patterns is not the typical driver. Jet streams (long, narrow bands of wind in upper atmosphere) are key in moving air masses.

Answer:

Long, narrow bands of wind blow in the upper atmosphere.