Why must passengers wear a seat belt during take off and landing?

Passengers must wear a seat belt during takeoff and landing to ensure their safety during critical phases of flight when the aircraft is most vulnerable to turbulence and sudden changes in altitude. In the event of an unexpected incident, such as sudden braking or a rough landing, seat belts help secure passengers in their seats, reducing the risk of injury. Additionally, wearing seat belts promotes compliance with aviation regulations and enhances overall safety for everyone on board.