What is one of the signs of carbon monoxide poisoning?

The correct choice relates to one of the symptoms commonly associated with carbon monoxide poisoning. Blurred vision can occur as a result of oxygen deprivation in the brain due to carbon monoxide's interference with the blood's ability to carry oxygen. As carbon monoxide binds to hemoglobin more readily than oxygen, it leads to a decrease in the amount of oxygen available to vital organs, including the brain, which can manifest in various neurological symptoms, including blurred vision.

Other symptoms of carbon monoxide poisoning can include headaches, dizziness, confusion, weakness, and nausea, which stem from this same lack of oxygen. Increased energy would be an unlikely sign, as the effects of carbon monoxide poisoning typically result in fatigue or lethargy rather than an increase in energy levels. Understanding these symptoms is crucial for pilots, as carbon monoxide can result from engine exhaust, making awareness of this condition essential for flight safety.