What action does pitch control in an aircraft?

Pitch control in an aircraft is responsible for managing the aircraft's nose orientation, which directly affects its altitude. When the pitch control is adjusted, it results in the aircraft going up or down. This is achieved through the manipulation of the elevators located on the tail of the aircraft. By raising or lowering these surfaces, the pilot can angle the nose up to climb or down to descend.

In contrast, the other options relate to different types of control. Rolling left or right pertains to the aircraft’s roll axis and is managed by ailerons, while turning left or right involves yaw control, typically handled by the rudder. Speed variation is influenced by throttle control, which adjusts engine power but does not directly affect the pitch. Thus, the action of pitch control is directly aligned with the vertical movement of the aircraft, making "go up or down" the accurate association for this question.