What is considered 'Moderate' turbulence intensity?

Moderate turbulence intensity is characterized primarily by frequent or abrupt changes in altitude, as described in the correct answer. This level of turbulence is noticeable to passengers and can lead to an increase in the difficulty of control for the pilots. It can cause some discomfort, but it is not as intense as severe turbulence, which would induce significant distress.

In the context of turbulence intensity classifications, moderate turbulence typically results in the aircraft experiencing changes that require the pilot to actively manage control but does not necessarily disrupt the flight path to the extent seen in severe turbulence. By clarifying that the intensity of moderate turbulence can be recognized through these changes, it helps define the operational expectations and response required from pilots during flight.