If the oxygen levels are between 8-10% by volume, what symptoms are likely to occur?

When oxygen levels in the atmosphere drop to between 8-10% by volume, the body begins to experience serious symptoms due to insufficient oxygen for normal functioning. The critical levels of oxygen below the standard 20.9% present in normal air significantly affect the brain and other vital organs.

At these low oxygen levels, fainting and loss of consciousness can occur because the brain, which is highly sensitive to oxygen deprivation, is among the first to be impacted. When oxygen is insufficient, it can lead to hypoxia, where the body’s tissue and organs are not receiving enough oxygen, leading to confusion, inability to move, and ultimately, if prolonged, loss of consciousness. This is consistent with the severe effects seen at dangerously low oxygen concentrations, making it the most likely symptom set for this range.

In contrast, the other choices reflect symptoms that manifest with varying degrees of oxygen deficiency but do not align as closely with the specific range of 8-10%. For example, shortness of breath and nausea is more typical at slightly higher but still deficient oxygen levels, while severe headaches and blurred vision often occur in different contexts. Rapid heartbeat and sweating might be seen in other conditions but are not the primary symptoms experienced under the specific circumstances outlined in