What is a primary role of crew members sitting in a jumpseat during flight?

The primary role of crew members sitting in a jumpseat during flight is to be secured during taxi, takeoff, landing, and turbulence. This is crucial for ensuring both the safety of the crew members and the passengers. Jumpseats are designed for crew members to secure themselves using seatbelts to prevent injuries during any unexpected events, such as sudden turbulence or an emergency situation.

During these critical phases of flight, the crew must be ready to take action if necessary and maintain order and safety in the cabin. The other options, while important aspects of cabin service, do not primarily address the critical safety requirement of secured positions during the flight's most vulnerable moments.