Which of the following best describes the conditions of moderate turbulence?

Moderate turbulence is characterized by the sensation that passengers feel as the aircraft experiences changes in altitude and attitude, leading to a noticeable but manageable level of movement. In this condition, passengers may feel a distinct pushing or pulling sensation, which can cause them to move against their seatbelts. This level of turbulence is significant enough to be felt, requiring passengers to remain seated with their seatbelts fastened for safety.

The other conditions described do not align with the characteristics of moderate turbulence. For instance, unsecured items flying around the cabin would indicate a higher level of turbulence, which exceeds what is typically described as moderate. Similarly, the absence of visible strain on passengers would suggest a calmer experience, more akin to light turbulence. The description of minimal movement while ensuring safety pertains more to light turbulence, which is not reflective of moderate conditions.