Final answer:
Cars with crumple zones reduce injuries by increasing the time of impact during a collision, which decreases the forces on passengers.
Step-by-step explanation:
A way to prevent injuries in a collision is to design cars with parts that can crumple or collapse, which help protect the passengers. The correct answer to how this helps is a. It reduces injury to the passengers by increasing the time of impact. In the event of an accident, a longer impact time means the force exerted on the car and its occupants is spread out over a longer period, resulting in less forceful impacts and thereby reducing injuries. Cars now come with features like airbags and dashboard padding which also serve to increase the time over which the force acts on occupants, reducing the forces they experience.