Which of the following is a common symptom of a concussion?

A common symptom of a concussion includes headache and confusion. Headaches often arise as a direct result of the trauma to the head, which may trigger various biochemical processes and lead to pain. Confusion, on the other hand, stems from the impact on cognitive function, making it difficult for the individual to process information, concentrate, or retain memories. Both symptoms are typical manifestations of the brain's response to injury, reflecting the disturbance in normal neurological function following a concussion.

While other symptoms such as increased sensitivity to light can also occur, they are not as universally recognized as the hallmark symptoms of headache and confusion. Redness in the eyes and sudden weight loss are not associated with concussions and do not align with the typical presentation of this type of brain injury.