How quickly can coma occur in an atmosphere with 4-6% oxygen?

In an atmosphere with 4-6% oxygen, coma can occur extremely quickly due to hypoxia, which is a deficiency in the amount of oxygen reaching the tissues. The brain is highly sensitive to oxygen deprivation, and within a very short period, a person can lose consciousness and enter a comatose state. Research indicates that unconsciousness can arise within seconds to a couple of minutes in such low-oxygen environments.

The option stating that coma can occur in 40 seconds aligns with the rapid onset of symptoms seen with severe hypoxia. This timeframe highlights the urgent need for immediate intervention in situations where oxygen levels are critically low. The other timeframes, such as 1 minute, 2 minutes, or 8 minutes, do not accurately reflect the typical speed of onset of coma associated with such dangerous oxygen levels.