Which of the following must all riders be doing, in addition to being seated within the cab or body, before the apparatus is put into motion?

All riders must be wearing seat belts before the apparatus is put into motion to ensure their safety during transport. The use of seat belts is a fundamental safety measure that significantly reduces the risk of injury in the event of an accident or sudden stop. When properly secured, seat belts help keep occupants in place, preventing them from being thrown around inside the vehicle or ejected from it during an emergency response.

While wearing universal precaution equipment, carrying extra personal protective clothing, and wearing helmets may be important safety practices in certain contexts, they do not directly relate to the requirement for securing passengers in the vehicle. Ensuring that everyone is buckled in is a strict safety protocol that applies universally to maintain the safety of all individuals aboard the emergency vehicle while in motion.