Which gas is known to shut down the nervous system?

The correct answer is carbon monoxide (CO). This gas is particularly harmful because it binds with hemoglobin in the blood more effectively than oxygen does, which reduces the blood's ability to carry oxygen to the brain and other vital organs. When oxygen levels diminish, the nervous system begins to malfunction, leading to symptoms such as dizziness, headaches, confusion, and even loss of consciousness.

While oxygen is essential for sustaining life and proper brain function, high levels of carbon dioxide can lead to respiratory acidosis and impaired function of the nervous system, but they do not inherently "shut down" the nervous system in the same manner that carbon monoxide does. Nitrogen, on the other hand, is a relatively inert gas and does not directly affect the functioning of the nervous system under normal circumstances.