Loss of cabin pressure may result in hypoxia because as cabin altitude increases:

As cabin altitude increases, the partial pressure of oxygen in the cabin air decreases. This is critical because our bodies rely on a certain partial pressure of oxygen to effectively absorb it into the bloodstream for use. Even though the percentage of oxygen in the air remains roughly the same (about 21%), the physical impact of reduced atmospheric pressure at higher altitudes means that there is less oxygen available in terms of partial pressure.

When this partial pressure drops, it can lead to hypoxia, a condition where the body does not receive enough oxygen to function effectively. Hypoxia can cause a variety of symptoms ranging from confusion, fatigue, and diminished cognitive ability to loss of consciousness, which is why maintaining cabin pressure at safe levels is a key aspect of aircraft safety.

The other options do not directly address the cause of hypoxia related to cabin altitude changes. While the percentage of other gases like nitrogen and carbon dioxide are relevant at different points, they do not effectively explain the hypoxic conditions created by a decrease in oxygen's availability due to lowering pressure at high altitudes.