What type of turbulence is characterized by abrupt changes?

The correct choice indicates that extreme turbulence is the type characterized by abrupt changes. Extreme turbulence can result in sudden and severe changes in altitude and attitude, making it dangerous for aircraft and uncomfortable for passengers. It may occur unexpectedly, causing the aircraft to experience violent and erratic movements, which significantly impacts both the pilots and the flight's stability. Recognizing the characteristics of extreme turbulence is vital for ensuring safety and managing the aircraft effectively during flight operations.

This understanding is critical in differentiating between the various levels of turbulence, where moderate turbulence typically encompasses less severe disruptions, and severe turbulence is intense but may not consistently lead to violent changes. Occasional turbulence is not a specific severity but rather indicates the frequency of its occurrence, making it less applicable to the abrupt change characteristic that defines extreme turbulence.