The question is asking us to fill in the gaps in the following sentence: When a person loses consciousness due to a head injury from a car crash, the (gap) keeps the body functioning by regulating the flow of information between the brain and the rest of the body. The best answer is that the gap should be filled by "autonomous nervous system" - this system is the one that is not controlled consciously, but one that is working in the background to make sure our body functions work properly.
