Which is a symptom of a concussion?

Nausea and vomiting are indeed classic symptoms associated with a concussion. A concussion is a type of traumatic brain injury that can occur due to a blow to the head or body, leading to disturbances in brain function. When the brain is affected, various physical and cognitive symptoms can arise. Nausea and vomiting occur as part of the body's response to injury, particularly when there is increased intracranial pressure or dysfunction of the brain's control centers.

Other symptoms of a concussion may include headache, dizziness, confusion, balance issues, and sensitivity to light or noise. While nausea and vomiting can also be seen in other medical conditions, in the context of a concussion, they are significant red flags prompting further evaluation.

In this question, the other options—broken bones, cramping in limbs, and fever—do not directly relate to the typical symptoms of a concussion. Broken bones are associated with musculoskeletal injuries, cramping in limbs is more related to muscle strain or dehydration, and fever indicates an infection or inflammation rather than a brain injury like a concussion. Thus, nausea and vomiting specifically point to changes or disturbances in brain function, making it the correct response in this case.