What is the consequence of oxygen levels falling below 10 percent?

When oxygen levels in the environment drop below 10 percent, the human body struggles to obtain the oxygen necessary for vital functions. This significant reduction in oxygen can lead to a loss of consciousness as the brain does not receive enough oxygen to operate effectively. As low oxygen levels persist, individuals may experience an eventual cessation of breathing, which can be life-threatening.

In contrast, while other choices might illustrate symptoms or effects related to different oxygen deprivation levels or other conditions, the specific consequence of oxygen falling below 10 percent directly correlates with serious impairment of consciousness and respiratory function. Thus, the identification of loss of consciousness and cessation of breathing as a consequence aligns accurately with the physiological limitations imposed by such low oxygen levels.