Final answer:
Properly adjusted seat head restraints prevent whiplash and should be at a level with the back of the head, playing a key role in neck protection during car accidents.
Step-by-step explanation:
Understanding Seat Head Restraints in Vehicle Safety
Properly adjusted seat head restraints serve a critical safety function in vehicles. The correct answer to the question is B. Both A and C. This means that properly adjusted seat head restraints (1) Are designed to prevent whiplash if hit from behind and (3) Should always be at a level with the back of the head. Whiplash is a type of neck injury caused by a sudden and rapid forward and backward movement of the neck, often as a result of a rear-end car accident. The anterior longitudinal ligament, located at the anterior side of the vertebral column, helps in resisting excess backward bending of the column, crucially protecting the neck. An appropriately positioned head restraint stabilizes the head and neck during a collision, thereby reducing the likelihood of injury to the ligament.
Safety features such as airbags and crumple zones in vehicles also contribute to reducing the severity of injuries. Crumple zones help protect passengers by increasing the time over which a collision occurs, thereby reducing the force exerted on the passengers. Airbags reduce the net force on occupants over a longer period during sudden stops, minimizing the force that brings the occupant to a stop.