Final answer:
Spinal cord injury is the most injury-causing thing that can happen to a person in a crash. It can lead to paralysis and the loss of ability to feel or move parts of the body.
Step-by-step explanation:
The most injury-causing thing that can happen to a person in a crash is a spinal cord injury. Spinal cord injuries make it difficult for messages to travel between the brain and body, and they can lead to paralysis, where a person loses the ability to feel or move parts of the body. The severity and location of the injury determine the extent of paralysis, such as quadriplegia or paraplegia.